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rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 1 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet features ? digital compensation of sensor offset, sensitivity, temperature drift and non-linearity ? accommodates differential sensor signal spans from 1.2mv/v to 60mv/v ? zacwire tm one-wire interface. ? internal temperature compensation and detection via bandgap ptat* ? optional sequential output of both temperature and bridge readings on zacwire tm digital output ? output options: rail-to-rail analog output voltage, absolute analog voltage, digital one-wire-interface ? supply voltage 2.7 to 5.5v, with external jfet 5.5v to 30v ? current consumption, depending on adjusted sample rate: 0.25ma to 1ma ? wide operational temperature: ?50 to +150c ? fast response time 1ms(typical) ? high voltage protection up to 30v with external jfet ? chopper-stabilized true differential adc ? buffered and chopper-stabilized output dac * proportional to absolute temperature application circuit typical rbic lite tm application circuit benefits ? no external trimming components required ? pc-controlled configuration and calibration via one- wire interface ? simple, low cost ? high accuracy (0.1% fso @ -25 to 85c; 0.25% fso @ -40 to 125c) ? single pass calibration ? quick and precise ? suitable for battery-powered applications ? small sop8 package brief description the rbic lite ? is a cmos integrated circuit, which enables easy and precise calibration of resistive bridge sensors via eeprom. when mated to a resistive bridge sensor, it will digitally correct offset and gain with the option to correct offset and gain coefficients and linearity over temperature. a second order compensation can be enabled for temperature coefficients of gain and offset or bridge linearity. rbic lite ? communicates via zmd?s zacwire tm serial interface to the host computer and is easily mass calibrated in a windows ? environment. once cali- brated, the output sig? pin can provide selectable 0 to 1v, rail-to-rail ratiometric analog output, or digital serial output of bridge data with optional temperature data. ? development kit available ? multi-unit calibrator kit available ? support for industrial mass calibration available ? quick circuit customization possible for large production volumes
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 2 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet contents 1 circuit des cription ............................................................................................................ ................ 4 1.1 s ignal f low and b lock d iagram ..........................................................................................................................4 1.2 a nalog f ront e nd ............................................................................................................................... .................5 1.2.1 bandgap/ptat and pt at amplifier................................................................................................ ..............5 1.2.2 bridge supp ly .................................................................................................................. ..............................5 1.2.3 pre-amp block .................................................................................................................. ............................5 1.2.4 analog-to-digital converte r (adc) .............................................................................................. ..................5 1.3 d igital s ignal p rocessor ............................................................................................................................... .....6 1.3.1 eeprom......................................................................................................................... ..............................7 1.3.2 one-wire interface - zacwire tm ....................................................................................................................7 1.4 o utput s tage ............................................................................................................................... ........................7 1.4.1 digital to analog c onverter (out put da c)....................................................................................... ..............7 1.4.2 output buffer .................................................................................................................. ...............................8 1.4.3 voltage refere nce bl ock........................................................................................................ .......................8 1.5 c lock g enerator / p ower o n r eset (clkpor) .................................................................................................8 1.5.1 trimming the oscilla tor ........................................................................................................ .........................9 2 functional d escription......................................................................................................... ........... 9 2.1 g eneral w orking m ode ............................................................................................................................... ........9 2.2 zac wire tm c ommunication i nterface ................................................................................................................10 2.2.1 properties and parame ters ...................................................................................................... ...................10 2.2.2 bit enc oding ................................................................................................................... .............................11 2.2.3 write operation from master to rbic lite tm ...................................................................................................11 2.2.4 rbic lite tm read o peratio ns ............................................................................................................... ........11 2.2.5 high level protoc ol ............................................................................................................ .........................14 2.3 c ommand /d ata p air e ncoding ............................................................................................................................14 2.4 c alibration s equence : .............................................................................................................................. .........17 2.5 eeprom b its ............................................................................................................................... ......................19 2.6 c alibration m ath ............................................................................................................................... .................22 2.6.1 correction c oeffici ents ........................................................................................................ ........................22 2.6.2 interpretation of binary number s for correction coefficients: .................................................................. ...22 2.7 r eading eeprom c ontents ..............................................................................................................................2 6 3 application circu it examples ................................................................................................... ... 27 3.1 t hree -w ire r ail - to -r ail r atiometric o utput ...................................................................................................27 3.2 a nalog v oltage o utput ............................................................................................................................... ......28 3.3 t hree -w ire r atiometric o utput with o ver -v oltage p rotection ....................................................................29 3.4 d igital o utput ............................................................................................................................... .....................29
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 3 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 4 esd/latch-up- protection ........................................................................................................ ....... 29 5 pin configuration and package .................................................................................................. 30 6 ic charact eristics............................................................................................................. ............... 31 6.1 a bsolute m aximum r atings ............................................................................................................................... .31 6.2 r ecommended o perating c onditions .................................................................................................................31 6.3 e lectrical p arameters ............................................................................................................................... .......32 6.4 a nalog i nputs ............................................................................................................................... ......................33 6.5 t emperature c ompensation and t emperature o utput .....................................................................................34 6.6 h igh v oltage o peration ............................................................................................................................... .....35 7 die dimensions and pad coordi nates ........................................................................................ 36 7.1 d ie d imensions ............................................................................................................................... .....................36 7.2 p ad c oordinates ............................................................................................................................... .................37 8 test ........................................................................................................................... .............................. 37 9 reliability .................................................................................................................... ......................... 37 10 customiza tion.................................................................................................................. ................... 37 11 related do cuments.............................................................................................................. ............ 38
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 4 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 1 circuit description 1.1 signal flow and block diagram the rbic lite tm series of resistive bridge sensor interface ics were specifically designed as a cost-effective solution for sensing in building automation, indu strial, office automation and white goods applications. the rbic lite tm employs zmd?s high precision bandgap with proportional-to-absolute-temperature (ptat) output; low-power 14-bit analog-to-digital converter (a dc, a2d, a-to-d); and on-chip dsp core with eeprom to precisely calibrate the bridge output signal. three selectable outputs, two analog and one digital, offe r the ultimate in versatility across many applications. the rbic lite ? rail-to-rail ratiometric analog output v out signal (0 to 5v v out @ v dd =5v) suits most building automation and automotive requirements. typical office automation and white goods applications require the 0~1v out signal, which in the rbic lite ? is referenced to the internal bandgap. direct interfacing to p controllers is facilitated via zmd?s single-wire serial zacwire tm digital interface. rbic lite ? is capable of running in high-voltage (5.5-30v ) systems when combined with an external jfet. figure 1.1 ? rbic lite tm block diagram
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 5 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 1.2 analog front end 1.2.1 bandgap/ptat and ptat amplifier the bandgap/ptat provides the ptat signal to the adc, which allows accurate temperature conversion. in addition, the ultra-low ppm bandgap provides a stable vo ltage reference over temper ature for the operation of the rest of the ic. the ptat signal is amplified through a path in the pre-amp and fed to the adc for conversion. the most significant 12-bits of this convert ed result are used for temperature measurement and temperature correction of bridge readings. when temperature is output in digi tal mode only the most signif icant 8-bits are given. 1.2.2 bridge supply the voltage driven bridge is usually connected to v dd and ground. as a power savings feature, the rbic lite ? also includes a switched transistor to interrupt the bri dge current via pin 1 (bsink). the transistor switching is synchronized to the a-to-d conversion and released after finish ing the conversion. to ut ilize this feature, the low supply of the bridge should be co nnected to bsink instead of ground. depending on the programmable update rate, the aver age current consumption (including bridge current) can be reduced to approximately 20%, 5% or 1%. 1.2.3 pre-amp block the differential signal from the bridge is amplified th rough a chopper-stabilized instrumentation amplifier with very high input impedance designed for low noise and low dr ift. this pre-amp provides gain for the differential signal and re-centers its dc to v dd /2. the output of the pre-amp block is fed into the a-to-d converter. the calibration sequence performed by the digital core in cludes an auto zero sequence to null any drift in the pre-amp state over temperature. the pre-amp is nominally set to a gain of 24. other possible gain settings are 6, 12, and 48. the inputs to the pre-amp from (vbn/vbp pins) can be reversed via an eeprom configuration bit. 1.2.4 analog-to-digi tal converter (adc) a 14-bit/1ms 2 nd order charge-balancing adc is used to convert signals coming from the pre-amplifier. the converter, designed in full differential switched capacito r technique, is used for converting the various signals in the digital domain. this principle offers the following advantages: ? high noise immunity because of the diffe rential signal path and integrating behavior ? independent from clock frequency drift and clock jitter ? fast conversion time owing to second order mode four selectable values for the zero point of the input voltage allow conversion to adapt to the sensor?s offset parameter. together with the reverse input polarity mode, th is results in four possible zero point adjustments. the conversion rate varies with the programmed update ra te. the fastest conversation rate is 1k samples/s and the response time is then 1ms. based on a best fit, the integral nonlinearity (inl) is less then 4 lsb 14bit.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 6 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 1.3 digital signal processor a digital signal processor (dsp) is used for proces sing the converted bridge data as well as performing temperature correction and computing the temper ature value for output on the digital channel. the digital core reads correction coefficients from eeprom and can correct for 1. bridge offset 2. bridge gain 3. variation of bridge offset over temperature (tco) 4. variation of bridge gain over temperature (tcg) 5. a single second order effect (sot) (second order term) the eeprom contains a single sot that can be app lied to correct one and only one of the following: ? 2 nd order behavior of bridge measurement ? 2 nd order behavior of tco ? 2 nd order behavior of tcg (for more details, see section 2.5.1.) if the sot applies to correcting the bridge reading th en the correction formula for the bridge reading is represented as a two step process as follows: zb = gain b [1 + t * tcg ]*[ br_raw + offset b + t * tco ] br = zb *(1.25+ sot * zb ) where: br = corrected bridge reading that is output as digital or analog on sig tm pin zb = intermediate result in the calculations br_raw = raw bridge reading from adc t_raw = raw temp reading converted from ptat signal gain_b = bridge gain term offset_b = bridge offset term tcg = temperature coefficient gain tco = temperature coefficient offset t = ( t_raw - t setl ) t_raw = raw temp reading converted from ptat signal t setl = t_raw reading at which low calibration was performed (typically 25c) sot = second order term note: see section 2.5.2.7 for limitations. if the sot applies to correcting 2 nd order behavior of tco then the formula for bridge correction is as follows: br = gain_b[1 + t*tcg]*[br_raw + offset _ b + t(sot* t + tco)] note: see section 2.5.2.7 for limitations.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 7 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet if the sot applies to correcting 2 nd order behavior of tcg then the formula for bridge correction is as follows: br = gain_b[1 + t(sot* t + tcg)]*[br_raw + offset_b _ + t*tco)] the bandgap reference gives a very linear ptat signal, so temperature correction can always simply be accomplished with a linear gain and offset term. corrected temp reading: t = gain_t *[ t_raw + offset_t ] where t_raw = raw temp reading converted from ptat signal offset_t = tempsensor offset coefficient gain_t = tempsensor gain coefficient 1.3.1 eeprom the eeprom contains the calibration c oefficients for gain and offset, etc., and the configuration bits, such as output mode, update rate, etc. when programming the eeprom, an internal charge pump voltage is used so a high voltage supply is not needed. the charge pump is internally regulated to 12.5 v voltage and the programming time amounts to 6ms. 1.3.2 one-wire interface - zacwire tm the ic communicates via a one-wire serial interfac e. there are different commands available for the following: ? reading the conversion result of the adc (get_br_raw, get_t_raw) ? calibration commands ? entering various test modes o dac test modes o oscillator, 1v, and pre-amp o eeprom test modes o oscillator override & scan test modes ? reading from the eeprom (dump of entire contents) ? writing to the eeprom (trim setting, configuration, and coefficients) 1.4 output stage 1.4.1 digital to analog converter (output dac) an 11-bit dac based on sub-ranging resistor strings is used for the digital-to-analog output conversion in the analog ratiometric and absolute analog voltage modes. se lection during calibration co nfigures the system to operate in either of these modes. the design allo ws for excellent testability as well as low power consumption.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 8 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 1.4.2 output buffer a rail-to-rail op amp configured as a unity gain buffer c an drive resistive loads (whet her pull-up or pull-down) as low as 2.5k and capacitances up to 15nf. in addition, to limit the error due to amplifier offset voltage, an error compensation circuit is included which tracks and reduces offset voltage to < 1mv. 1.4.3 voltage reference block this block uses the absolute reference voltage prov ided by the bandgap to produce two regulated on-chip voltage references. a 1v reference is used for the output dac high reference when the part is configured in 0-1v analog output mode. for this reason, the 1v referenc e must be very accurate and includes trim so that its value can be trimmed within +/- 2mv of 1.00v. the 1v reference is also used as the on-chip reference for the jfet regulator block so the regulation set point of the jfet regulator can be fine tuned using the 1v trim. 1v reference trim (1v vs. trim for nominal process run): 1vref_trim3 1vref_trim2 1vreft_trim1 1vref_trim0 1vref deltav 5vref deltav 1 1 1 1 -0.0184 -0.0920 1 1 1 0 -0.0161 -0.0805 1 1 0 1 -0.0138 -0.0690 1 1 0 0 -0.0115 -0.0575 1 0 1 1 -0.0092 -0.0460 1 0 1 0 -0.0069 -0.0345 1 0 0 1 -0.0046 -0.0230 1 0 0 0 -0.0023 -0.0115 0 1 1 1 nominal nominal 0 1 1 0 +0.0023 +0.0115 0 1 0 1 +0.0046 +0.0230 0 1 0 0 +0.0069 +0.0345 0 0 1 1 +0.0092 +0.0460 0 0 1 0 +0.0115 +0.0575 0 0 0 1 +0.0138 +0.0690 0 0 0 0 +0.0161 +0.0805 sample: programming ?0000? the trimmed voltage = nominal value + 0.0161v 1.5 clock generator / power on reset (clkpor) if the power supply exceeds 2.5v (max imum), the reset signal de-asserts and the clock generator starts working at a frequency of approximately 512khz (20 %). the exact value only influences the conversion cycle time and communication to the outside world but not the accuracy of signal processing. in addition, to minimize the oscillator error as the v dd voltage changes, an on-chip regulator is used to supply the oscillator block.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 9 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 1.5.1 trimming the oscillator trimming is performed at wafer level, and it is strongly recommended that this not be changed during calibration because zacwire tm communication is no longer guaranteed at different oscillator frequencies. trimming bits delta frequency (khz) 100 +385 101 +235 110 +140 111 +65 000 nominal 001 -40 010 -76 011 -110 sample: programming ?011? the trimmed frequency = nominal value ? 110khz 2 functional description 2.1 general working mode the command/data transfer takes place via the one-wire sig ? pin using the zacwire tm serial communication protocol. after power on the ic waits for 6ms(=com mand window) for the start_cm command. without this command, the normal operation mode (n om) starts. in this mode, raw bridge values are converted, and the corrected values are presented on the output in analog or digital format (depending on the configuration stored in eeprom). command mode (cm) can only be entered during the 6ms command window after power on. if the ic receives the start_cm command during the command window, it remains in the command mode. the cm allows changing to one of the other modes via command. after command start_rw, the ic is in the raw mode. without correction, the raw values are transmitt ed to the digital output in a predefined order. the rm can only be stopped by power off. raw mode is used by the calibration software for collection of raw bridge and temperature data so the correction coefficients can be calculated.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 10 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet figure 2.1 ? general working mode 2.2 zacwire tm communication interface 2.2.1 properties and parameters parameter symbol min typ max unit comments 1 pull-up resistor (on-chip) r zac,pu 30 k : on-chip pull-up resistor switched on during digital output mode and during cm mode (first 6ms power up) 2 zacwire tm rise time t zac,rise 5 p s any user rc network included in sig tm path must me e t this rise time 3 zacwire ? line resistance r zac,line 3.9 2 k : also see section 6.3 4 zacwire tm load capacitance c zac,load 0 1 15 nf also see section 6.3 5 voltage level - low v zac,low 0 0.2 v dd rail-to-rail cmos driver 6 voltage level - high v zac,high 0.8 1 v dd rail-to-rail cmos driver normal operation mode command mode measurement cycle stopped full command set command routine will be processed after each command start_cm start_nom start_rm no command raw mode power off no commands possible measurement cycle conditioning calculation (corrected bridge and temperature values) depending on the con- figuration, the sig tm pin is ? 0v-1v ? rail-to-rail ratiometric ? digital output diagnostics functions measurement cycle sig tm pin provides raw bridge and temperature values in the format bridge_high (1 st byte) bridge_low (2 nd byte) temp (3 rd byte) power on command window (6ms) send start cm
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 11 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 6 5 7 3 4 2 0 1 p 7 s 6 5 3 4 2 0 1 p command byte data byte s 2 2 p 19-bit frame (write) start bit data bit (example: bit 2) command bit (example: bit 2) parity bit command byte or parity bit data byte 2.2.2 bit encoding start bit => 50% duty cycle used to set up strobe time logic 1 => 75% duty cycle logic 0 => 25% duty cycle figure 2.2 ? duty cycle manchester 2.2.3 write operation from master to rbic lite tm the calibration master sends a 19-bit packet frame to the ic. figure 2.3 ? 19-bit write frame the incoming serial signal will be sampled at a 512khz clo ck rate. this protocol is ve ry tolerant to clock skew and can easily tolerate baud rates in the 6khz to 48khz range. 2.2.4 rbic lite tm read operations the incoming frame will be checked for proper parity on both command and data bytes, as well as for any edge timeouts prior to a full frame being received. once a command/data pair is received, the rbic lite tm will perform that command. once the command has been successfully executed by the ic , it will acknowledge success by a tr ansmission of an a5h byte back to the master. if the master does not receive an a5h tr ansmission within 130msec of issuing the command, it must assume the command was either impr operly received or could not be executed. bit window start bit logic 1 logic 0
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 12 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 1 s 0 1 0 0 1 1 0 p data byte s 1 0 p 1 data byte packet 10-bit byte a5h start bit data bit (high) data bit (low) parity bit data byte 0 s 0 5 3 4 2 0 1 p data byte bridge high ? stop s 6 7 5 7 3 4 2 0 1 p data byte bridge low 2 data byte packet digital bridge output start bit ? stop bit data bit (example: bit 2) parity bit data byte s 2 p ? stop 0 s 0 5 3 4 2 0 1 p data byte bridge high ? sto p s 6 7 5 7 3 4 2 0 1 p data byte bridge low s 6 7 5 7 3 4 2 0 1 p data byte temperature 3 data byte packet digital bridge output with temperature ? sto p figure 2.4 ? read acknowledge the rbic lite tm transmits 10-bit bytes (1 start bit, 8 data, 1 parity). during calibration and configuration, transmissions are normally either a5h or data. a5h i ndicates successful completion of a command. there are two different digital output modes configurable (digital output with temperature and digital output with only bridge data). during normal operation mode, if the part is configured for digital output of the bridge reading, it first transmits the high byte of bridge data followed by the low byte. the bridge data is 14-bits in resolution, so the upper two bits of the high byte are always zero padded. there is a half stop bit time between bytes in a packet. that means for the time of a half a bit width, the signal level is high. figure 2.5 ? digital output (nom) bridge readings the second different digital output mode is digital outpu t bridge reading with temperature. it will be transmitted as 3 data packets. the temperatur e byte represents an 8-bit temper ature quantity spanning from ?50c to 150c. figure 2.6 ? digital output (nom) bridge readings with temperature
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 13 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet s 0 7 5 0 3 4 2 0 1 p ? stop s 6 7 5 7 idle time 2 0 1 p 3 4 s 0 7 5 0 3 4 2 0 1 p ? stop s 6 7 5 7 idle time 2 0 1 p 3 4 s 0 7 5 0 4 idle time 3 6 5 2 0 1 p 3 4 packet transmission (this example shows 2 data packets.) the eeprom transmission occurs in a packet wi th 14 data bytes as shown in figure 2.7. figure 2.7 ? read eeprom contents there is a variable idle time between packets. this idle time varies with the update rate setting in eeprom. figure 2.8 ? transmission of a number of data packets the table below shows the idle time between packets vers us update rate. this idle time can vary by nominal +/-15% between parts and over a temperature range of ?50c to 150 c update rate setting: idle time between packets: 00 1ms 01 4.85ms 10 22.5ms 11 118ms transmissions from the ic occur at one of tw o speeds depending on the update rate programmed in eeprom. if the user chooses one of the two fastest update rates (1ms or 5ms) then the baud rate of digital transmission will be 32khz. if howev er, the user chooses one of the two slower update rates (25ms or 125ms), then the baud rate of digital transmission will be 8khz. one can easily program any standard controller to communi cate with the rbic lite tm . zmda can provide sample code for a microchip pic controller.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 14 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 2.2.5 high level protocol the rbic lite tm will listen for a command/data pair to be transmi tted for the 6ms after the de-assert of its internal power on reset (por). if a tr ansmission is not received within this time frame, then it will transition to normal operation mode (nom). in nom, it will out put bridge data in either 0-1v analog, rail-to-rail ratiometric analog output, or digital depending on how the part is currently configured. if the rbic lite tm receives a start cm command within the first 6ms after the de-assert of por, then it will go into command mode(cm). in this mode, calibrati on/configuration commands will be executed. the rbic lite tm will acknowledge successful execution of commands by transmission of an a5h. the calibrating/configuring master will know a command was not successfully execut ed if no response is received after 130ms of issuing the command. once in command interpreting/executing mode, the rbic lite tm will stay in this mode until power is removed, or a start nom (start normal operat ion mode) command is received. the start cm command is used as an interlock mechanism to prevent a sp urious entry into command mode on power up. the first command received within the 6ms window of por must be a start cm command to enter into command interpreting mode. any other commands will be ignored. 2.3 command/data pair encoding the 16-bit command/data stream sent to the rbic lite tm can be broken into four 4-bit nibbles. the most significant nibble encodes the command. the 2 nd nibble is reserved for possible future expansion, and should be sent as ?0x0?. the last two nibbles encode the data byte. command nibble: data: description: 0h 0xxh read eeprom command via sig tm pin. 2h 0yxh enter test mode (subset of command mode for testing purpose only): sig tm pin will assume the value of different internal test points, depending on most significant nibble of data sent. y = 0h => internal oscillator y = 1h => 2.5v reference y = 2h => ptat y = 3h => pre-amp output+ y = 4h => scan mode (sdo* routed to sig tm pin, part goes into clock override mode and scan mode) y = 5h => dac ramp testmode. gain_b[13:3] contains the starting point, and the increment is (offset_b/8). the increment will be added every 125usec. y = 6-7h => part goes into clock override mode. y = 8-fh => undefined.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 15 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet command nibble: data: description: 3h x => don?t care h => hex 0wdh w => what d => data h => hex trim/configure: 3 rd nibble determines what is trimmed/configured. 4 th nibble is data to be programmed. 3 rd nibble 4 th data nibbles description: 0h xh trim oscillator least significant 3 bits of data used. 1h xh trim 1v reference. least significant 4 bits of data used. 2h xh offset mode. least significant 2 bits of data used. 3h xh set output mode. least significant 2 bits used. 4h xh set update rate. least significant 2 bits used. 5h xh configure jfet regulation 6h xh program the tc_cfg register. least significant 3-bits used. most significant bit of data nibble should be 0. 7h xh program bits [99:96] of eeprom. {sot_cfg,pamp_gain} 8h xh clear all case: used to clear all bits in eeprom to 0. 9h xh 0101? case: used to set whole eeprom to alternating pattern. ah xh 1010?case: used to set opposite alternating pattern. bh xh set all case: used to set all bits in eeprom to 1. ch xh eeprom endurance mode. initial setting of offset_b[13:3] determines the # of cycles. offset_t must be programmed to zero initially. 7h & c-fh xh reserved.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 16 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet command nibble: data: description: 4h 000h start nom => ends command mode, transition to normal operation mode mode. 4h 010h start raw mode (rm) in this mode if gain_b = 800h, and gain_t = 80h then the digital output will simply be the raw values of the a2d for the bridge reading, and the ptat conversion. 5h 000h start cm => start the command mode, used to enter command interpret mode. if data is sent with this command then that data sets up the star t data for the dac test mode. 6h 0yyh program sot (2 nd order term). 7h 0yyh program t setl 8h 0yyh program gain_b upper 7-bits (set msb of yy to 0.) 9h 0yyh program gain_b lower 8-bits ah 0yyh program offset_b upper 6-bi ts (set two msbs of yy to 0.) bh 0yyh program offset_b lower 8-bits ch 0yyh program gain_t dh 0yyh program offset_t eh 0yyh program tco fh 0yyh program tcg *sdo: scan data out
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 17 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet calibration sequence: although the rbic lite tm can function with many different types of resi stive bridges, assume it is connected to a pressure bridge for the following calibration example. in this case, calibration essentia lly involves collecting raw bridge and temperature data from the rbic lite tm for different known pressures and temperatures. this raw data can then be processed by the calibration master (the pc), and the calculated coefficients c an then be written to the eeprom of the rbic lite tm . zmda can provide software and hardware with samples to perform the calibration. there are three main steps to calibration: 1. assigning a unique identification to the ic. this identification is programmed in eeprom and can be used as an index into the database stored on the ca libration pc. this database will contain all the raw values of bridge readings and temp reading for that part, as well as the known pressure and temperature the bridge was exposed to. this unique identification can be stored in a combination of the following eeprom registers t setl , tcg, tco. these registers will be overwritten at the end of the calibration process, so this unique identification is not a permanent serial number. 2. data collection. data collection involves getting ra w data from the bridge at different known pressures and temperatures. this data is then stored on the cali bration pc using the unique identification of the ic as the index to the database. 3. coefficient calculation and write. once enough dat a points have been collected to calculate all the desired coefficients then the coefficients can be calculat ed by the calibrating pc and written to the ic. step 1 assigning unique identification assigning a unique identification number is as simple as using the commands program tsetl, program tcg, and program tco. these 3 8-bit registers will allow for 16meg unique devices. in addition gain_b needs to be programmed to 800h (unity) and gain_t needs to be programmed to 80h (unity). step 2 data collection the number of different unique (pressure, temperatur e) points that calibration needs to be performed at depends on the customer?s needs. the minimum is a 2-point calibration, and the maximum is a 5-point calibration. to acquire raw data from the part one has to get rbic lite tm to enter raw mode. this is done by issuing a start cm (start command mode 5000h) comm and to the ic followed by a start rm (start raw mode 4010h) command with the lsb of the upper data nibbl e set. now if the gain_b term was set to unity (800h) and the gain_t term was also set to unity (80h) then the part will be in the raw mode and will be outputting raw data on its sig tm pin instead of corrected bridge and temperature. the calibration system should now grab several of these data points (16 each of bridge and temperature is recommended) and average them. these raw bridge and temperature setting should be stored in the database along with the known pressure and temperature. the ouput format during raw mode is bridge_high, bridge_low, temp. each of these being 8-bit quantities. the upper 2-bits of bridge_high are zero filled. the temp data (8-bits only) would not really be enough info for accurate tem perature calibration. therefore the upper three bits of temp information are not given, but rather assumed kn own. therefore effectively 11-bits of temperature information is provided in this mode.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 18 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet step 3 coefficient calculations the math to perform the coefficient calculation is very complicated and will not be discussed in detail. there is a rough overview in the ?calibration math? section. rather zmda will provide software to perform the coefficient calculation. zmda can also provide source code of the algorithms in a c code format. once the coefficients are calculated the final step is to write them to the eeprom of the rbic lite tm . the number of calibration points required can be as few as two or as many as five. this depends on the precision desired, and the behavior of the resistive bridge in use. 1. 2-point calibration would be used if one simply wanted a gain and offset term for a bridge with no temperature compensation for either term. 2. 3-point calibration would be used if one wanted to have 1 st order compensation for the tco. 3. 3-point calibration could also be used if one wanted 2 nd order correction for the bridge, but no temperature compensation of the bridge output. 4. 4-point calibration would be used if one wanted 1 st order compensation for both tco and tcg. 5. 4-point calibration could also be used if one wanted 1 st order compensation for the tco and 2 nd order correction for the bridge measurement. 6. 5-point calibration would be used if one wanted both 1 st order tco correction and 1 st order tcg correction, plus a 2 nd order correction that could be applied to one and only one of the following: 2 nd order tco, 2 nd order tcg, or 2 nd order bridge.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 19 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 2.4 eeprom bits programmed through the serial interface: eeprom range description note 2:0 osc_trim see the table in the ?trimming the oscillator? section for complete data 100 => fastest 101 => 3 clicks faster than nominal . 111 => 1 click faster than nominal 000 => nominal 001 => 1 click slower than nominal . 010 => 2 clicks slower than nominal 011 => slowest 6:3 1v_trim/jfet_trim see table in the ?voltage reference block? section. 8:7 a2d_offset offset selection: 11 => [-1/2,1/2] mode bridge inputs 10 => [-1/4,3/4] mode bridge inputs 01 => [-1/8,7/8] mode bridge inputs 00 => [-1/16,15/16] mode bridge inputs to change the bridge signal polarity set tc_cfg[3](=bit 87) 10:9 output_select 00 => digital (3-bytes with parity) bridge high {00,[5:0]} bridge low [7:0] temp [7:0] 01 => 0-1v analog 10 => rail-to-rail ratiometric analog output 11 => digital (2-bytes with parity) (no temp) bridge high {00,[5:0]} bridge low [7:0] 12:11 update_rate 00 => 1 msec (1khz) 01 => 5 msec (200hz) 10 => 25 msec (40hz) 11 => 125 msec (8 hz)
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 20 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet eeprom range description note 14:13 jfet_cfg 00 => no jfet regulation (lower power) 01 => no jfet regulation (lower power) 10 => jfet regulation centered around 5.0v 11 => jfet regulation centered around 5.5v (i.e. over-voltage protection). 29:15 gain_b bridge gain: gain_b[14] => mult x 8 gain_b[13:0] => 14-bit unsigned number representing a number in the range [0,8). 43:30 offset_b signed 14-bit offset for bridge correction 51:44 gain_t temperature gain coefficient used to correct ptat reading. 59:52 offset_t temperature offset coefficient used to correct ptat reading. 67:60 t setl stores raw ptat reading at temperature in which low calibration points were taken 75:68 tcg coefficient for temperature correction of bridge gain term. tcg = 8-bit magnitude of tcg term. sign is determined by tc_cfg (bits 87:84) 83:76 tco coefficient for temperature correction of bridge offset term. tco = 8-bit magnitude of tco term. sign and scaling are determined by tc_cfg (bits 87:84) 87:84 tc_cfg this 4-bit term determines options for temperature compensation of the bridge. tc_cfg[3] => if set, bridge signal polarity flips tc_cfg[2] => if set tcg is negative tc_cfg[1] => scale magnitude of tco term by 8, and if sot applies to tco, scale sot by 8. tc_cfg[0] => if set tco is negative
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 21 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet eeprom range description note 95:88 sot 2 nd order term. this term is a 7-bit magnitude with sign. sot[7] = 1 ? negative sot[7] = 0 ? positive sot[6:0] = magnitude [0-127] this term can apply to a 2 nd order tcg, tco or bridge correction. (see tc_cfg above) 99:96 {sot_cfg, pamp_gain} bits [99:98] = sot_cfg 00 = sot applies to bridge 01 = sot applies to tcg 10 = sot applies to tco 11 = prohibited note: for more details, see section 2.5.1. bits [97:96] = pre-amp gain 00 => 6 01 => 24 (default setting) 10 => 12 11 => 48 (only the default gain setting (24) is tested at the factory, all other gain settings are not guaranteed)
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 22 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 2.5 calibration math 2.5.1 correction coefficients (all terms calculated external to the dut and t hen programmed to eeprom th rough serial interface) gain_b = gain term used to compensate span of bridge reading. offset_b = offset term used to compensate offset of bridge reading gain_t = gain term used to compensate span of temp reading offset_t = offset term used to compen sate offset of temp reading sot = second order term. this term can be used applied as a second order correction term for: 1. the bridge measurement 2. temperature coefficient of offset (tco) 3. temperature coefficient of gain (tcg) eeprom bits 99:98 determine what sot applies to. note: there are limitations for the sot for t he bridge measurement and for the sot for the tco which are explained in section 2.5.2.7. t setl = raw ptat reading at low temperature at which calibration was performed (typically at room temp) tcg = temperature correction coefficient of bridge gain term this term has a 8-bit magnitude and a sign bit (tc_cfg[2]). tco = temperature correction coefficient of bridge offset term this term has a 8-bit magnitude, a sign bit (t c_cfg[0]) and a scaling bit (tc_cfg[1])which can multiply its magnitude by 8. 2.5.2 interpretation of binary numbers for correction coefficients: br_raw should be interpreted as an unsigned number in the set [0,16383] with resolution of 1. t_raw should be interpreted as an unsigned number in the set [0,16383] with resolution of 4
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 23 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 2.5.2.1 gain_b interpretation gain_b should be interpreted as a number in the set [0,8). the msb (bit 14) is a scaling bit that will multiply the effect of the gain_b term by 8. the remaining bits (gain_b[13:0]) represent a number in the range of [0,8) with gain_b[13] having a weighting of 4, and each s ubsequent bit has a weighting of ? the previous bit. table 2.1 ? gain_b weightings bit position: weighting: 13 4 12 2 11 1 . . . 1 2 -10 0 2 -11 examples: the binary number: 010010100110001 = 4.6489; the scaling number is 0 so there is no multiply by 8 of the number represented by gain_b[13:0] the binary number: 101100010010110 = 24.586; the scaling nu mber is 1 so there is a multiply by 8 of the number represented by gain_b[13:0] limitation: using the 5-point calibration 5pt-tcg&tc o&sot_tco (including the second order sot_tco), the gain_b is limited to a value equal or less than 8 (instead of 64). 2.5.2.2 offset_b interpretation offset_b is a 14-bit signed binary number in two?s co mplement form. the msb has a weighting of ?8192. the following bits then have a weighting of: 4096, 2048, 1024, ? table 2.2 ? offset_b weightings bit position: weighting: 13 -8192 12 4096 11 2048 . . . 1 2 1 = 2 0 2 0 = 1 thus the binary number: 11111111111100 = -4
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 24 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 2.5.2.3 gain_t interpretation gain_t should be interpreted as a number in the set [0,2). gain_t[7] has a weighting of 1, and each subsequent bit has a weighting of ? the previous bit. table 2.3 ? gain_t weightings bit position: weighting: 7 1 6 0.5 5 0.25 . . . 1 2 -6 0 2 -7 2.5.2.4 offset_t interpretation offset_t is an 8-bit signed binary number in two?s complement form. the msb has a weighting of ?128. the following bits then have a weighting of: 64, 32, 16 ? table 2.4 ? offset_t weightings bit position: weighting: 7 -128 6 64 . . . 1 2 1 = 2 0 2 0 = 1 thus the binary number: 00101001 = 41 2.5.2.5 tco interpretation tco is specified as an 8-bit magnitude with an additional sign bit (tc_cfg[0]) and a sc alar bit (tc_cfg[1]). when the scalar bit is set, the signed tco is multiplied by 8. tco resolution: 0.175uv/v/ o c (input referred) tco range: +/- 44.6uv/v/ o c (input referred)
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 25 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet if the scaling bit is used then the above resolution and range are scaled by 8 to give tco scaled resolution: 1.40uv/v/ o c input referred tco scaled range: +/- 357uv/v/ o c input referred 2.5.2.6 tcg interpretation tcg is specified as an 8-bit magnitude wi th an additional sign bit (tc_cfg[2]). the resolution of tcg is: 17.0ppm/ o c the range of tcg is: +/- 4335ppm/ o c 2.5.2.7 sot interpretation sot is a second order term that can apply to one and only one of the following: bridge non-linearity correction, tco non-linearity correcti on, or tcg non-linearity correction. as it applies to bridge non-linearity correction: the resolution is: 0.25% @ full scale the range is: +25% @ full scale to -25% @ full scale (saturation in internal arithmetic will occur at greater negative non-linearities) limitation: using the 5-point calibration method for which so t_br is applied to the bridge measurement, there is a possibility of calibration math overflow. this only occurs if the sensor input exceeds 200% of the calibrated full span, which means the highest applied pressure should never go higher than this value. 1 as it applies to tcg: the resolution is: 0.3 ppm/( o c) 2 the range is: +/- 38ppm/( o c) 2 as it applies to tco: 2 settings are possible. it is possible to scale the effect of sot by 8. if tc_cfg[1] is set, then both tco and sot?s contribution to tco are multiplied by 8. 1 example of the limitation when sot is applied to the bridge reading this example of the limitation when so t is applied to the bridge reading uses a pressure sensor bridge that outputs -10mv at the lowest pressure of interest. that point is ca librated to read 0%. the same sensor outputs +40mv at the highest pressure of interest. that point is calibrated to read 100%. this sensor has a 50mv span over the pressure range of in terest. if the sensor were to experience an over-pressure event that took the sensor out put up to 90mv (200% of span), the internal ca lculations could overflow. the result would be a corrected bridge reading that would not be saturated at 100% as expected but instead read a value lower than 100%. this problem only occurs when sot is applied to correct the bridge reading.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 26 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet resolution at unity scaling: 1.51nv/v/( o c) 2 (input referred) range: +/- 0.192 v/v/( o c) 2 (input referred) resolution at 8x scaling: 12.1nv/v/( o c) 2 (input referred) range: +/- 1.54 v/v/( o c) 2 (input referred) limitation: if the second order term sot applies to tco, the bridge gain gain_b is limited to values equal or less than 8 (instead of 64). 2.6 reading eeprom contents the contents of the entire eeprom memory can be read out using the read eeprom command (00h). this command will cause the ic to output consecutive bytes on the zacwire tm . the interpretation of these bytes is given in the following table. read eeprom (bit order): bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 byte 1: offset_b[7:0] byte 2: gain_t[1:0] offset_b[13:8] byte 3: offset_t[1:0] gain_t[7:2] byte 4: t setl [1:0] offset_t[7:2] byte 5: tcg[1:0] t setl [7:2] byte 6: tco[1:0] tcg[7:2] byte 7: tc_cfg[1:0] tco[7:2] byte 8: sot[5:0] tc_cfg[3:2] byte 9: osc_trim[1:0] sot_cfg[3:0]* sot[7:6] byte 10: output_select[0] a2d_offse t[1:0] 1v_trim[3:0]** osc_trim[2] byte 11: gain_b[2:0] jfet_cfg[1:0 ] update_rate[1:0] output_select[1] byte 12: gain_b[10:3] byte 13: offset_b[3:0]*** gain_b[14:11] byte 14: a5h * sot_cfg/pamp_gain ** 1v_trim/jfet_trim *** duplicates first 4 bits of byte 1
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 27 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 3 application circuit examples typical output analog load resistor r l = 10k (minimum 2.5k ). this optional load resistor can be configured as a pull-up or pull-down. if it is configured as a pull- down, it cannot be part of the module to be calibrated because this would prevent proper operation of the zacwire tm . if a pull-down load is desired, it must be added to system after module calibration. there is no output load capacitance needed. eeprom contents: output_select, jfet_cfg, 1v_trim/jfet-trim 3.1 three-wire rail-to-rail ratiometric output figure 3.1 ? rail-to-rail ratiometric voltage output , temperature compensation via internal ptat. the optional bridge sink allows a power savings of bridge current. the output voltage can be either a) rail-to-rail ratiometric analog output v dd (=vsupply). b) 0 to 1v analog output is also possible. the absolute voltage output reference is trimmable 1v (+/-2mv) in the 1v output mode via a 4-bit eeprom field. (see section 1.4.3.)
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 28 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 3.2 analog voltage output figure 3.2 ? absolute voltage output with temperature compensation via internal temperature ptat external jfet regulation for all industry standard applications the output signal range is either a) 0 to 1v analog output. the absolute voltage output refere nce is trimmable 1v (+/-2mv) in the 1v output mode via a 4-bit eeprom field. (see section 1.4.3.) b) rail-to-rail analog output. the on-chip reference for the jfet regulator block is trimmable 5v (+/-~10mv) in the ratiometric output mode via a 4-bi t eeprom field. (see section 1.4.3.)
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 29 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet v supply out ground optional bsink 1 bsink 2 vbp vgate 5 3 n/c 4 v bn vdd 6 sig tm 7 v ss 8 0.1 f j107 vishay + 5 ... + 5.5 v 3.3 three-wire ratiometric output with over-voltage protection figure 3.3 ? ratiometric output, temper ature compensation via internal diode in this application, the jfet is used for voltage prot ection. the jfet_cfg bits (14:13) in eeprom are configured to 5.5v. there is an additional maximal error of 8mv caused by non-zero r on of the limiter jfet. 3.4 digital output for all three circuits the output signal can also be digita l. depending from the output select bits bridge signal or the bridge signal and temperature signal are sent. for the digital output no load resistor or load capacity ar e necessary. no pull down resistor is allowed. if a line resistor or pull up resistor is used, the re quirement for the rise time must be met ( 5 s). the ic output includes a pull up resistor of about 100k . the digital output can easily be read by firmware from a microcontroller and zmd can provid e the customer with software in developing the interface. 4 esd/latch-up-protection all pins have an esd protection of >4000v and a latch-up protection of 100ma or of +8v/ ?4v (to vss/vssa). esd protection referred to the human body model is tested wi th devices in sop-8 packages during product qualification. the esd test follows t he human body model with 1.5kohm/100pf based on mil 883, method 3015.7.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 30 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 2 3 1 4 8 7 6 5 5 pin configuration and package figure 5.1 ? rbic lite tm pin out diagram the standard package of the rbic lite tm is sop-8 (3.81mm body (150mil) wide) with lead-pitch. 1.27mm (50mil). pin-no. name description 1 bsink optional ground connection for bridge ground. used for power savings 2 vbp positive bridge connection 3 n/c no connection 4 vbn negative bridge connection 5 vgate gate control for external jfet regulation/over- voltage protection 6 vdd supply voltage (2.7-5.5v) 7 sig tm zacwire tm interface (analog out, digital out, calibration interface) 8 vss ground supply
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 31 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 6 ic characteristics 6.1 absolute maximum ratings parameter symbol min typ max units analog supply voltage v dd -0.3 6.0 v voltages at analog i/o ? in pin v ina -0.3 v dd +0.3 v voltages at analog i/o ? out pin v outa -0.3 v dd +0.3 v storage temperature range t stg -50 150 c storage temperature range t stg <10h -50 170 c 6.2 recommended operating conditions parameter symbol min typ max units analog supply voltage to gnd v dd 2.7 5.0 5.5 v analog supply voltage (with external jfet regulator) v supp 5.5 7 30 v ambient temperature range 1&2 t amb -50 150 c external capacitance between v dd and gnd c vdd 100 220 470 nf output load resistance to v ss or v dd 3 r l,out 2.5 10 k output load capacitance 4 c l,out 10 15 nf bridge resistance r br 0.2 5 100 k power on rise time t pon 100 ms 1 note that the maximum calibration temperature is 85c. 2 if buying die, designers should use cauti on not to exceed maximum junction temperature by proper package selection. 3 when using the output for digital calibration, no pull down resistor is allowed. 4 using the output for digital calibration, c l,out is limited by the maximum rise time t zac,rise . 5 note: minimum bridge resistance is only a factor if using the bsink feature. the nominal r ds (on) of the bsink transistor is 10 ? when operating at vdd=5v, and 15 ? when operating at v dd =3.0v. this does give rise to a ratiomet ricity inaccuracy that becomes greater with low bridge resistances.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 32 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 6.3 electrical parameters parameter symbol conditions min typ max units supply voltage / regulation supply voltage v dd 2.7 5.0 5.5 v at minimum update rate. 250 supply current (varies with update rate and output mode) i dd at maximum update rate. 1000 ? temperature -10 c to 120 c 35 ppm/k* temperature coefficient ? regulator (worst case) tc reg temperature <-10 c and>120 c 100 ppm/k* power supply rejection ratio psrr dc < 100 hz (jfet regulation loop using mmbf4392 and 0.1 f decoupling cap) 60 db * power supply rejection ratio psrr ac < 100 khz (jfet regulation loop using mmbf4392 and 0.1 f decoupling cap) 45 db * power-on reset level por 1.4 2.6 v analog to digital converter (adc) resolution r adc 14 bit common mode voltage v cm 1 v dda -1.3 v integral nonlinearity (inl) inl adc based on ideal slope -4 +4 lsb 1 differential nonlinearity (dnl) dnl adc -1 +1 lsb * response time t res,adc varies with update rate. value given at fastest rate. 1 ms analog output parameters (dac + buffer) max. output current i out max current maintaining accuracy 2.2 ma resolution r out referenced to v dd 11 bit absolute error e abs dac input to output -10 +10 mv differential nonlinearity dnl no missing codes -0.9 +1.5 lsb 11bit * upper output voltage limit v out r l =2.5k 95% v dd lower output voltage limit v out 2.5 mv zacwire ? serial interface * zacwire ? line resistance r zac,line 3.9 2 k zacwire ? load capacitance c zac,load 0 1 15 2 nf
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 33 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet parameter symbol conditions min typ max units zacwire ? rise time t zac,rise 5 s voltage level low v zac,low 0 0.2 v dd voltage level high v zac,low 0.8 1 v dd total system start-up-time t sta power-up to output 10 ms response time t resp update_rate=<1ms 1 2 ms sampling rate f s update_rate=<1ms 1000 hz supply current i dd update_rate=<1ms 1 ma overall linearity error e lind bridge input to output -- digital 0.025 0.04 % overall linearity error e lina bridge input to output -- analog 0.1 0.2 % overall ratiometricity error re out not using bsink feature 0.035 % overall accuracy ? digital (only ic, without sensor bridge) ac outd -25 c to 85 c -40 c to 125 c 3 0.1% 0.25% %fso %fso overall accuracy ? analog (only ic, without sensor bridge) ac outa -25 c to 85 c -40 c to 125 c 3 0.25% 0.35% %fso %fso * the parameters with an * under ?units? are tested by design. 1 note this is +/- 4 lsbs to the 14-bit a-to-d conversion. th is implies absolute accuracy to 12-bits on the a-to-d result. non- linearity is typically better at temperatures less than 125c. 2 the rise time must be t zac,rise = 2 r zac,line * c zacload 5 s . if using a pull up resistor instead of a line re sistor, it must meet this specification. 3 overall accuracy specifications for ?50c to 150c are pending. 6.4 analog inputs rbic lite t m incorporates an extended 14-bit charge-balanced adc which allows for a single gain setting on the pre-amplifier to handle bridge sensitivities from 1.2 to 36mv/v while maintaining 8 to 12 bits of output resolution (default analog gain 24). the tables below illustrate the minimum resolution achievable for a variety of bridge sensitivities. analog gain 12 input span (mv/v) min typ max allowed offset (+/- % of span) 1 minimum guaranteed resolution (bits) 43.3 60.0 79.3 3% 13.0 36.1 50.0 66.1 17% 12.7 25.3 35.0 46.3 53% 12.2 18.0 25.0 33.0 101% 11.7 14.5 20.0 26.45 142% 11.4
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 34 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet analog gain 12 input span (mv/v) min typ max allowed offset (+/- % of span) 1 minimum guaranteed resolution (bits) 7.2 10.0 13.22 351% 10.4 3.6 5.0 6.6 767% 9.4 1 in addition to tco,tcg analog gain 24 input span (mv/v) min typ max allowed offset (+/- % of span) 1 minimum guaranteed resolution (bits) 16 25.0 36 25% 12.6 12.8 20.0 28.8 50% 12 6.4 10.0 14.4 150% 11 3.2 5.0 7.2 400% 10 1.6 2.5 3.6 900% 9 0.8 1.2 1.7 2000% 8 1 in addition to tco,tcg analog gain = 48 input span (mv/v) min typ max allowed offset (+/- % of span) 1 minimum guaranteed resolution (bits) 10.8 15.0 19.8 3% 13 7.2 10.0 13.2 35% 12.4 4.3 6.0 7.9 100% 11.7 2.9 4.0 5.3 190% 11.1 1.8 2.5 3.3 350% 10.4 1.0 1.4 1.85 675% 9.6 0.72 1.0 1.32 975% 9.1 1 in addition to tco,tcg 6.5 temperature compensation and temperature output a highly-linear bandgap/ptat circuit is used in order to produce a signal which can be used in compensation of the bridge over temperature. in addition, when digital mode is activated both bridge and temperature signals (8-bit temperature quantity) can be broadcast on the zacwire tm pin.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 35 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 6.6 high voltage operation a linear regulator control circuit is included on the ic to interface with an external jfet to allow for operation in systems where the supply voltage ex ceeds 5.5v. this circuit can also be used for over-voltage protection. the regulator set point has a coarse adjust (eeprom bit) that can adjust the set point around 5.0 or 5.5v. in addition, the 1v trim will also act as a fine adjust for t he regulation set point. note: if using the external jfet for over-voltage protection purposes (i.e., 5v at jfet drai n and expecting 5v at jfet source), there will be a voltage drop across the jfet, thus ratiometricity will be compromised somewhat depending on the rds(on) of the chosen jfet. a vishay j107 is the best choice t hat would produce only an 8mv drop worst case. if using as regulation instead of over-vol tage, a mmbf4392 also works well.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 36 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 7 die dimensions and pad coordinates 7.1 die dimensions ? die size (including scribeline): 2230m x 1681m 3.75sqmm ? core die size (without scribeline): 2080m x 1531m 3.19sqmm ? die thickness: 390m ? scribeline (distance between two core dice on wafer): 150m ? pads size: 68m x 68m
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 37 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 7.2 pad coordinates all pads coordinates are for pad centers and related to the corner. name x coordinate in y coordinate in bsink 106.3 85.9 por_n 1109.7 85.9 vbp 1210.0 85.9 vdd 1389.3 77.3 vbn 1568.1 85.9 vss 107.2 1444.7 vssa 198.3 1444.7 vpp 356.1 1444.7 sig_pd 1428.6 1444.7 vdd 1672.3 1435.8 vgate 1809.2 1444.7 8 test the test program is based on this datasheet. the final parameters that w ill be tested during se ries production are listed in the tables of section 6.3. the digital part of the ic includes a scan path, which can be activated and controlled during wafer test. it guarantees failure coverage more than 98%. further test support for testing of the analog parts on wafer level is included in the dsp. 9 reliability a reliability investigation according to the in -house non-automotive standard will be performed. 10 customization for high-volume applications, which require an up- or downgraded functionality compared to the zm31010, zmd can customize the circuit design by adding or removing certain functional blocks. for it zmd has a considerable library of sensor-dedicated circuitry blocks. thus zmd can provide a custom solution quickly. please contact zmd for further information.
rbic lite ? datasheet, rev. 1.2, february 28, 2006 page 38 of 38 ? zmd ag, 2006 all rights reserved. the material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnis hed in this publication is prelim inary and subject to changes wit hout notice. zmd31010 rbic lite tm low-cost sensor signal conditioner datasheet 11 related documents ? zmd31010 rbic lite tm development kit documentation ? zmd31010 rbic lite tm ssc kits feature sheet (includes ordering codes and price information) ? zmd31010 rbic lite tm technical notes ? rev_a_production ? zmd31010 rbic lite tm application notes ? in-circuit programming boards ? zmd31010 rbic lite tm die dimensions and pad coordinates ? zmd31010 rbic lite tm mass calibrator kit documentation for the most recent revisions of this document and of the related documents, please go to www.zmd.biz this information applies to a product under development. its characteristics and specif ications are subject to change without n otice. zmd assumes no obligation regarding future manufacture unless otherwi se agreed in writing. the information furnished hereby is beli eved to be correct and accurate. however, zmd shall not be liable to any customer, licensee or any other third party for any damages in connection with or arising out of the furnis hing, performance or use of this technica l data. no obligation or liability to any customer, licensee or any other third party shall result from zmd?s rendering of technical or other services. for further information: zmd ag grenzstrasse 28 01109 dresden, germany phone +49 (0)351-8822-366 fax +49 (0)351-8822-337 sales@zmd.de www.zmd.biz zmd america, inc. 201 old country road, suite 204 melville, ny 11747, usa phone +01 (631) 549-2666 fax +01 (631) 549-2882 sales@zmda.com www.zmd.biz

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