HMC1023 sensor products 3-axis magnetic sensor features x ball grid array (bga) surface-mount package x three orthogonal magneto-resistive sensors x wide field range of 6 gauss x 1.0 mv/v/gauss sensitivity x minimum detectable field to 85 p gauss x patented on-chip set/reset and offset straps product description the honeywell HMC1023 is a high performance three- axis magneto-resistive sensor design in a single package. the advantages of the HMC1023 include orthogonal three-axis sensing, small size and a 16- contact bga surface mount package. each of the magneto-resistive sensors are configured as 4-element wheatstone bridges to convert magnetic fields to differential output voltages. capable of sensing fields down to 85 micro-gauss, these sensors offer a compact, high sensitivity and highly reliable solution for low field magnetic sensing. applications HMC1023 circuit diagram x compassing x navigation systems x attitude reference x traffic detection x medical devices solid state electronics center ? www.magneticsensors.com ? (800) 323-8295 ? page 1 4 .com u datasheet
HMC1023 sensor products specifications characteristics conditions* min typ max units bridge elements supply vbridge referenced to gnd 1.8 5.0 12 volts resistance bridge current = 5ma, vcc to gnd 250 350 450 ohms operating temperature ambient -40 125 c storage temperature ambient, unbiased -55 125 c humidity tested at 121c 100 % field range full scale (fs) ? total applied field -6 +6 gauss linearity error best fit straight line 1 gauss 3 gauss 6 gauss 0.05 0.4 1.6 %fs hysteresis error 3 sweeps across 3 gauss 0.08 %fs repeatability error 3 sweeps across 3 gauss 0.08 %fs bridge offset offset = (out+) ? (out-) field = 0 gauss after set pulse, vcc = 5v -10 2.5 +10 mv sensitivity set/reset current = 2.0a 0.8 1.0 1.2 mv/v/gauss noise density @ 1khz, vcc=5v 48 nv/sqrt hz resolution 50hz bandwidth, vcc=5v 85 p gauss bandwidth magnetic signal (lower limit = dc) 5 mhz disturbing field sensitivity starts to degrade. use s/r pulse to restore sensitivity. 20 gauss sensitivity tempco t a = -40 to 125c, vcc=5v t a = -40 to 125c, icc=5ma -2800 -3000 -600 -3200 ppm/c bridge offset tempco t a = -40 to 125c, no set/reset t a = -40 to 125c, with set/reset 500 10 ppm/c bridge ohmic tempco vcc=5v, t a = -40 to 125c 2100 2500 2900 ppm/c cross-axis effect cross field = 1 gauss, happlied = 1 gauss +0.3 %fs max. exposed field no perming effect on zero reading 200 gauss sensitivity ratio of x,y,z sensors t a = -40 to 125c 1005 % x,y, z sensor orthogonality sensitive direction in x, y and z sensors 1.0 degree * tested at 25 c except stated otherwise. solid state electronics center ? www.magneticsensors.com ? (800) 323-8295 ? page 2 4 .com u datasheet
HMC1023 sensor products specifications characteristics conditions* min typ max units set/reset strap resistance measured from s/r+ to s/r- 2.0 3.0 4.0 ohms current 0.1% duty cycle, or less, 2 p sec current pulse 1.5 2.0 4.0 amp resistance tempco t a = -40 to 125c 3300 3700 4100 ppm/c offset straps resistance measured from offset+ to offset- 40 50 60 ohms offset constant dc current field applied in sensitive direction 4.0 4.6 6.0 ma/gauss resistance tempco t a = -40 to 125c 3500 3900 4300 ppm/c * tested at 25 c except stated otherwise. pin configuration (arrows indicate direction of applied field that generates a positive output voltage after a set pulse.) package outline solid state electronics center ? www.magneticsensors.com ? (800) 323-8295 ? page 3 4 .com u datasheet
HMC1023 sensor products mounting considerations when mounting the honeywell HMC1023 on a circuit board, please consider the following advice for ball grid array component attachment. ball grid array attachment/removal to printed circuit boards is precisely controlled thermal solder reflow process. to prevent internal electrical damage and package cracking, do not use conventional soldering iron/solder station tools. if you do not have experience and the reflow oven, please have a qualified bga rework technician do the work for you. the reflow profile show below is the recommended profile for HMC1023 package attachment. melting temperature for the HMC1023 balls is at 180c. the recommended rise and fall temperatures should be no greater than 3c/sec to prevent mechnical stresses or ?popcorning?. peak external temperature the part should be exposed to is between 200 to 210c. when exposed a high temperature, such as the solder reflow process, the internal connections in the package could sustain permanent damage, leaving open connections. 225c is the melting point of solder inside the HMC1023 ball grid array package. do not expose the part to this level of temperature. if using solder paste, we recommend kester sn62 solder paste with water soluble flux r560. this has a melting point around 180c. kester recommends a pre-heating zone from ambient temperature to 180c for 2 to 4 minutes maximum. the first part of this pre-heating zone ramps up from ambient to 150c in 90 seconds with a ramp rate of less than 2.5 degrees c per second. the soak zone should last from 60 to 90 seconds (2 minutes maximum) and ramp up in temperature from 150 to 180c at 0.5 to 0.6 c/ sec. the reflow zone should last for 30 to 90 seconds maximum (40 to 60 seconds is ideal) and peak in temperature between 200 and 210c with a ramp of 1.3 to 1.6c/sec. solid state electronics center ? www.magneticsensors.com ? (800) 323-8295 ? page 4 the reflow parameters can vary significantly and excellent reflow results can still be achieved. a thin layer of paste flux or a 2 to 3 mil layer of solder paste applied to the mother-board prior to placing the HMC1023 is helpful. the profile can be verified by placing a thermocouple between the HMC1023 and motherboard. 4 .com u datasheet
HMC1023 sensor products basic device operation the honeywell HMC1023 magneto-resistive sensor is composed of three wheatstone bridge elements to measure magnetic fields for both field strength and direction. with power applied to the bridges, the sensors elements convert any incident magnetic field in each element?s sensitive axis direction to a differential voltage output. in addition to the bridge elements, these sensors have two types of on-chip magnetically coupled straps; the offset straps and the set/reset strap. these straps are honeywell patented features for incident field adjustment and magnetic domain alignment; and eliminate the need for external coils positioned around the sensors. the magnetoresistive sensors are made of a nickel-iron (permalloy) thin-film deposited on a silicon wafer and patterned as a resistive strip element. in the presence of a magnetic field, a change in the bridge resistive elements causes a corresponding change in voltage across the bridge outputs. these resistive elements are aligned together to have a common sensitive axis (indicated by arrows on the pinouts) that will provide positive voltage change with magnetic fields increasing in the sensitive direction. because the output only is in proportion to the one-dimensional axis (the principle of anisotropy) and its magnitude, additional sensor bridges placed at orthogonal directions permit accurate measurement of arbitrary field direction. the combination of sensor bridges in this three orthogonal axis configuration permit applications such as compassing and magnetometry. the individual sensor offset straps allow for several modes of operation when a direct current is driven through it. these modes are: 1) subtraction (bucking) of an unwanted external magnetic field, 2) null-ing of the bridge offset voltage, 3) closed loop field cancellation, and 4) auto-calibration of bridge gain. the set/reset strap can be pulsed with high currents for the following benefits: 1) enable the sensor to perform high sensitivity measurements, 2) flip the polarity of the bridge output voltage, and 3) periodically used to improve linearity, lower cross-axis effects, and temperature effects. noise characteristics the noise density for the hmr1023 series is around 50nv/sqrt hz at the 1 hz corner, and drops below 10nv/sqrt hz at 20hz and begins to fit the johnson noise value at around 5nv/sqrt hz beyond 100hz. the 10hz noise voltage averages around 0.58 micro-volts with a 0.16 micro-volts standard deviation. these values are provided with a 5-volt supply. offset strap the offset strap is a spiral of metalization that couples in the sensor element?s sensitive axis. in the HMC1023 design, there is one strap per bridge with both ends brought out externally. each offs et strap measures nominally 50 ohms, and requires about 4.6ma for each gauss of induced field. the straps will easily handle currents to buck or boost fields through the 6 gauss linear measurement range, but designers should note the extreme thermal heating on the sensor die when doing so. with most applications, the offset strap is not utilized and can be ignored. designers can leave one or both strap connections (off- and off+) open circuited, or ground one connection node. do not tie positive and negative strap connections together of the same strap to avoid shorted turn magnetic circuits. set/reset strap the set/reset strap is another spiral of metalization that couples to the sensor elements easy axis (perpendicular to the sensitive axis on the sensor die). the HMC1023 set/reset strap circuit has three straps (one per sensor) paralleled together for operation at low voltages. the set/reset strap connections have a nominal resistance of 3.0 ohms with a minimum required peak current of 1.5a for reset or set pulses. with rare exception, the set/reset strap must be used to periodically condition the magnetic domains of the magneto-resistive elements for best and reliable performance. a set pulse is defined as a positive pulse current entering the s/r+ strap connection. the successful result would be the magnetic domains aligned in a forward easy-axis direction so that the sensor bridge?s polarity is a positive slope with positive fields on the sensitive axis result in positive voltages across the bridge output connections. solid state electronics center ? www.magneticsensors.com ? (800) 323-8295 ? page 5 4 .com u datasheet
HMC1023 sensor products a reset pulse is defined as a negative pulse current entering the s/r+ strap connection. the successful result would be the magnetic domains aligned in a reverse easy-axis direction so that sensor bridge?s polarity is a negative slope with positive fields on the sensitive axis result in negative voltages across the bridge output connections. typically a reset pulse is sent first, followed by a set pulse a few milliseconds later. by shoving the magnetic domains in completely opposite directions, any prior magnetic disturbances are likely to be co mpletely erased by the duet of pulses. for simpler circuits with less critical requirements for noise and accuracy, a single polarity pulse circuit may be employed (all sets or all resets). with these uni-polar pulses, several pulses together become close in performance to a set/reset pulse circuit. figure 1 shows a quick and dirty manual pulse circuit for uni-polar application of pulses to the set/reset strap. rsr 3.0 rsr 3.0 iset 5 volts iset 5 volts figure 1 set pulse circuit application notes three axis compassing with tilt compensation for full three-axis compassing, the circuit depicted in figure 2 shows HMC1023 used for sensing the magnetic field in three axes. a two-axis accelerometer with digital (pwm) outputs is also shown to provide pitch and roll (tilt) sensing, to correct the three-axis magnetic sensors outputs into to the tilt-compensated two-axis heading. the accelerometer can be substituted with a fluidic 2-axis tilt sensor if desired. for lower voltage operation with lithium battery supplies (2.5 to 3.6vdc), the set/reset circuit should be upgraded from a single irf7509 to the dual irf7509 implementation (h-bridge) to permit a minimum 1.5-ampere pulse (500ma per set/reset strap resistance) to the sensors. figure 7 three axis compass HMC1023 u1 vcc set/reset .33uf irf7509 set/reset vcc/2 vcc/2 5.00k 5.00k 500k 500k 5.00k 5.00k 500k 500k lmv324 lmv324 1nf 1nf u3 u4 3.3 to 5.0v u2 vcc vcc/2 5.00k 5.00k 500k 500k lmv324 .1 p f + - p c with multiplexed a/d conv. an0 an1 an2 an3 vcc/2 u6 u5 xout yout two-axis accelerometer vcc vcc do0 di0 di1 HMC1023 u1 vcc set/reset .33uf irf7509 set/reset vcc/2 vcc/2 5.00k 5.00k 500k 500k 5.00k 5.00k 500k 500k lmv324 lmv324 1nf 1nf u3 u4 3.3 to 5.0v u2 vcc vcc/2 5.00k 5.00k 500k 500k lmv324 .1 p f + - p c with multiplexed a/d conv. an0 an1 an2 an3 vcc/2 u6 u5 xout yout two-axis accelerometer vcc vcc do0 di0 di1 solid state electronics center ? www.magneticsensors.com ? (800) 323-8295 ? page 6 4 .com u datasheet
HMC1023 sensor products duty cycling for lower energy consumption for battery powered and other applications needing limited energy consumption, the sensor bridge and support electronics can be switched ?off? between magnetic field measurements. the HMC1023 sensors are very low capacitance (bandwidth > 5mhz) sensor bridges and can stabilize quickly, typi cally before the support electronics can. other energy saving ideas would be to minimize the quantity of set/reset pulses which saves energy over the battery life. figure 3 shows a simple supply switching circuit that can be microprocessor controlled to duty cycle (toggle) the electronics in moderate current (<25ma) applications. mmbt2907alt1 p c to sensor circuits toggle 10k : + - 10 p f 0.01 p f vcc vcc gnd *mmbd7001lt1 * used when vcc = 5.0 volts, jumper when using vcc = 3.3 volts or less. mmbt2907alt1 p c to sensor circuits toggle 10k : + - 10 p f 0.01 p f vcc vcc gnd *mmbd7001lt1 * used when vcc = 5.0 volts, jumper when using vcc = 3.3 volts or less. off on off on figure 3 duty cycling ordering information part number package style HMC1023 three axis magnetic sensor HMC1023pcb three axis magnetic sensor ? 16-pin dip demo the application circuits herein constitute typical us age and interface of ho neywell product. honeywell does not warrant or assume liability for customer-designed circuits derived from this description or depiction. honeywell reserves the right to make changes to improve reliability, function or design. honeywell does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others. this product may be covered by one or more of the following u.s. patents: 4569742 4681812 4847584 4857418 4945397 5019461 5247278 5820924 5952825 and 6529114. 900252 10-03 rev. b solid state electronics center ? www.magneticsensors.com ? (800) 323-8295 ? page 7 4 .com u datasheet
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