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| ? 2011 microchip technology inc. ds22234b-page 1 mcp1640/b/c/d features ? up to 96% typical efficiency ? 800 ma typical peak input current limit: -i out > 100 ma @ 1.2v v in , 3.3v v out -i out > 350 ma @ 2.4v v in , 3.3v v out -i out > 350 ma @ 3.3v v in , 5.0v v out ? low start-up voltage: 0.65v, typical 3.3v v out @ 1 ma ? low operating input voltage: 0.35v, typical 3.3v out @ 1 ma ? adjustable output voltage range: 2.0v to 5.5v ? maximum input voltage ? v out < 5.5v ? automatic pfm/pwm operation (mcp1640c): - pfm operation disabled (mcp1640b/d) - pwm operation: 500 khz ? low device quiescent current: 19 a, typical pfm mode ? internal synchronous rectifier ? internal compensation ? inrush current limiting and internal soft-start ? selectable, logic controlled, shutdown states: - true load disconnect option (mcp1640b) - input to output bypass option (mcp1640c/d) ? shutdown current (all states): < 1 a ? low noise, anti-ringing control ? overtemperature protection ? available packages: - 6-lead sot23 - 8-lead 2x3 dfn applications ? one, two and three cell alkaline and nimh/nicd portable products ? single cell li-ion to 5v converters ? li coin cell powered devices ? personal medical products ? wireless sensors ? handheld instruments ? gps receivers ? bluetooth headsets ? +3.3v to +5.0v distributed power supply general description the mcp1640/b/c/d is a compact, high-efficiency, fixed frequency, synchronous step-up dc-dc con- verter. it provides an easy-to-use power supply solution for applications powered by either one-cell, two-cell, or three-cell alkaline, nicd, nimh, one-cell li-ion or li-polymer batteries. low-voltage technology allows the regulator to start up without high inrush current or output voltage overshoot from a low 0.65v input. high efficiency is accomplished by integrating the low resistance n-channel boost switch and synchronous p-channel switch. all compensation and protection circuitry are integrated to minimize external components. for standby applications, the mcp1640 operates and consumes only 19 a while operating at no load, and provides a true disconnect from input to output while shut down (en = gnd). additional device options are available that operate in pwm-only mode and connect input to output bypass while shut down. a ?true? load disconnect mode provides input to output isolation while disabled by removing the normal boost regulator diode path from input to output. a bypass mode option connects the input to the output using the integrated low resistance p-channel mosfet, which provides a low bias keep-alive voltage for circuits operating in deep sleep mode. both options consume less than 1 a of input current. output voltage is set by a small external resistor divider. two package options are available, 6-lead sot23 and 8-lead 2x3 dfn. package types mcp1640 8-lead 2x3 dfn* p gnd s gnd en v outs v outp 1 2 3 4 8 7 6 5 sw v in v fb ep 9 4 1 2 3 6 v in v fb sw gnd en 5 v out mcp1640 6-lead sot23 * includes exposed thermal pad (ep); see table 3-1 . 0.65v start-up synchronous boost regulator with true output disconnect or input/output bypass option
mcp1640/b/c/d ds22234b-page 2 ? 2011 microchip technology inc. v in gnd v fb sw v in 0.9v to 1.7v v out 3.3v @ 100 ma c out 10 f c in 4.7 f l 1 4.7 h v out + - 976 k ? 562 k ? alkaline v in p gnd v fb sw v in 3.0v to 4.2v v out 5.0v @ 300 ma c out 10 f c in 4.7 f l 1 4.7 h v outs + - 976 k ? 309 k ? v outp s gnd li-ion en en efficiency vs. i out for 3.3v out 40.0 60.0 80.0 100.0 0.1 1.0 10.0 100.0 1000.0 output current (ma) efficiency (%) v in = 0.8v v in = 1.2v v in = 2.5v ? 2011 microchip technology inc. ds22234b-page 3 mcp1640/b/c/d 1.0 electrical characteristics absolute maximum ratings ? en, fb, v in, v sw , v out - gnd ........................... +6.5v en, fb ........... mcp1640/b/c/d ds22234b-page 4 ? 2011 microchip technology inc. temperature specifications pmos switch on resistance r ds(on)p ?0.9 ? ? v in = 3.3v, i sw = 100 ma nmos peak switch current limit i n(max) 600 850 ? ma note 5 v out accuracy v out % -3 ? +3 % includes line and load regulation; v in = 1.5v line regulation ??? v out / v out ) / ? v in | -1 0.01 1 %/v v in = 1.5v to 3v i out = 25 ma load regulation ?? v out / v out | -1 0.01 1 %i out = 25 ma to 100 ma; v in = 1.5v maximum duty cycle dc max 88 90 ? % switching frequency f sw 425 500 575 khz en input logic high v ih 90 ?? %of v in i out = 1 ma en input logic low v il ?? 20 %of v in i out = 1 ma en input leakage current i enlk ? 0.005 ? a v en = 5v soft-start time t ss ? 750 ? s en low to high, 90% of v out ; note 4 thermal shutdown die temperature t sd ? 150 ? ? c die temperature hysteresis t sdhys ? 10 ? ? c electrical specifications: parameters sym min typ max units conditions temperature ranges operating junction temperature range t j -40 ? +125 c steady state storage temperature range t a -65 ? +150 c maximum junction temperature t j ? ? +150 c transient package thermal resistances thermal resistance, 5l-tsot23 ? ja ? 192 ? c/w eia/jesd51-3 standard thermal resistance, 8l-2x3 dfn ? ja ?93 ?c/w dc characteristics (continued) electrical characteristics: unless otherwise indicated, v in = 1.2v, c out = c in = 10 f, l = 4.7 h, v out =3.3v, i out =15ma, t a = +25c. boldface specifications apply over the t a range of -40 o c to +85 o c. parameters sym min typ max units conditions note 1: 3.3 k ? resistive load, 3.3v out (1 ma). 2: for v in > v out , v out will not remain in regulation. 3: i q is measured from v out ; v in quiescent current will vary with boost ratio. v in quiescent current can be estimated by: (i qpfm * (v out /v in )), (i qpwm * (v out /v in )). 4: 220 ? resistive load, 3.3v out (15 ma). 5: peak current limit determined by characterization, not production tested. ? 2011 microchip technology inc. ds22234b-page 5 mcp1640/b/c/d 2.0 typical performance curves note: unless otherwise indicated, v in = en = 1.2v, c out =c in =10f, l =4.7h, v out =3.3v, i load =15ma, t a =+25c. figure 2-1: v out i q vs. ambient temperature in pfm mode. figure 2-2: v out i q vs. ambient temperature in pwm mode. figure 2-3: maximum i out vs. v in . figure 2-4: 2.0v v out pfm / pwm mode efficiency vs. i out . figure 2-5: 3.3v v out pfm / pwm mode efficiency vs. i out . figure 2-6: 5.0v v out pfm / pwm mode efficiency vs. i out . note: the graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. the performance characteristics listed herein are not tested or guaranteed. in some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 -40 -25 -10 5 20 35 50 65 80 ambient temperature (c) i q pfm mode (a) v out = 2.0v v out = 5.0v v out = 3.3v v in = 1.2v 150 175 200 225 250 275 300 -40 -25 -10 5 20 35 50 65 80 ambient temperature (c) i q pwm mode (a) v out = 3.3v v out = 5.0v v in = 1.2v 0 100 200 300 400 500 600 00.511.522.533.544.55 v in (v) i out (ma) v out = 3.3v v out = 2.0v v out = 5.0v 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 100 1000 i out (ma) efficiency (%) v out = 2.0v v in = 0.8v v in = 1.2v v in = 1.6v pwm / pfm pwm only 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 100 1000 i out (ma) efficiency (%) v out = 3.3v v in = 0.8v v in = 1.2v v in = 2.5v pwm / pfm pwm only 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 100 1000 i out (ma) efficiency (%) pwm / pfm pwm only v out = 5.0v v in = 1.2v v in = 1.8v v in = 2.5v mcp1640/b/c/d ds22234b-page 6 ? 2011 microchip technology inc. note: unless otherwise indicated, v in = en = 1.2v, c out =c in =10f, l =4.7h, v out =3.3v, i load =15ma, t a = +25c. figure 2-7: 3.3v v out vs. ambient temperature. figure 2-8: 3.3v v out vs. ambient temperature. figure 2-9: 3.3v v out vs. v in . figure 2-10: minimum start-up and shutdown v in into resistive load vs. i out . figure 2-11: f osc vs. ambient temperature. figure 2-12: pwm pulse skipping mode threshold vs. i out . 3.285 3.29 3.295 3.3 3.305 3.31 3.315 3.32 3.325 3.33 -40 -25 -10 5 20 35 50 65 80 ambient temperature (c) v out (v) i out = 15 ma v in = 0.8v v in = 1.8v v in = 1.2v 3.26 3.28 3.30 3.32 3.34 3.36 3.38 -40 -25 -10 5 20 35 50 65 80 ambient temperature (c) v out (v) i out = 15 ma v in = 1.5v i out = 50 ma i out = 5 ma 3.20 3.24 3.28 3.32 3.36 3.40 0.8 1.2 1.6 2 2.4 2.8 v in (v) v out (v) t a = - 40c i out = 5 ma t a = 25c t a = 85c 0.25 0.40 0.55 0.70 0.85 1.00 0 20406080100 i out (ma) v in (v) startup shutdown v out = 3.3v 480 485 490 495 500 505 510 515 520 525 -40 -25 -10 5 20 35 50 65 80 ambient temperature (c) switching frequency (khz) v out = 3.3v 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 012345678910 i out (ma) v in (v) v out = 3.3v v out = 5.0v v out = 2.0v ? 2011 microchip technology inc. ds22234b-page 7 mcp1640/b/c/d note: unless otherwise indicated, v in = en = 1.2v, c out =c in =10f, l =4.7h, v out =3.3v, i load =15ma, t a =+25c. figure 2-13: input no load current vs. v in . figure 2-14: n-channel and p-channel r dson vs. > of v in or v out . figure 2-15: pfm / pwm threshold current vs. v in . figure 2-16: mcp1640 3.3v v out pfm mode waveforms. figure 2-17: mcp1640b 3.3v v out pwm mode waveforms. figure 2-18: mcp1640/b high load waveforms. 10 100 1000 10000 0.8 1.1 1.4 1.7 2 2.3 2.6 2.9 3.2 3.5 v in (v) i in (a) v out = 3.3v v out = 5.0v v out = 2.0v v out = 2.0v v out = 3.3v v out = 5.0v pwm / pfm pwm only 0 1 2 3 4 5 1 1.5 2 2.5 3 3.5 4 4.5 5 > v in or v out switch resistance (ohms) p - channel n - channel 0 2 4 6 8 10 12 14 16 00.511.522.533.54 v in (v) i out (ma) v out = 2.0v v out = 3.3v v out = 5.0v mcp1640/b/c/d ds22234b-page 8 ? 2011 microchip technology inc. note: unless otherwise indicated, v in = en = 1.2v, c out =c in =10f, l =4.7h, v out =3.3v, i load =15ma, t a = +25c. figure 2-19: 3.3v start-up after enable. figure 2-20: 3.3v start-up when v in = v enable . figure 2-21: mcp1640 3.3v v out load transient waveforms. figure 2-22: mcp1640b 3.3v v out load transient waveforms. figure 2-23: mcp1640b 2.0v v out load transient waveforms. figure 2-24: 3.3v v out line transient waveforms. ? 2011 microchip technology inc. ds22234b-page 9 mcp1640/b/c/d 3.0 pin descriptions the descriptions of the pins are listed in tab l e 3 - 1 . table 3-1: pin function table 3.1 switch node pin (sw) connect the inductor from the input voltage to the sw pin. the sw pin carries inductor current and can be as high as 800 ma peak. the integrated n-channel switch drain and integrated p-channel switch source are inter- nally connected at the sw node. 3.2 ground pin (gnd) the ground or return pin is used for circuit ground con- nection. length of trace from input cap return, output cap return, and gnd pin should be made as short as possible to minimize noise on the gnd pin. in the sot23-6 package, a single ground pin is used. 3.3 enable pin (en) the en pin is a logic-level input used to enable or disable device switching, and lower quiescent current while disabled. a logic high (>90% of v in ) will enable the regulator output. a logic low (<20% of v in ) will ensure that the regulator is disabled. 3.4 feedback voltage pin (fb) the fb pin is used to provide output voltage regulation by using a resistor divider. the fb voltage will be 1.21v typical with the output voltage in regulation. 3.5 output voltage pin (v out ) the output voltage pin connects the integrated p-channel mosfet to the output capacitor. the fb voltage divider is also connected to the v out pin for voltage regulation. 3.6 power supply input voltage pin (v in ) connect the input voltage source to v in . the input source should be decoupled to gnd with a 4.7 f minimum capacitor. 3.7 signal ground pin (s gnd ) the signal ground pin is used as a return for the integrated v ref and error amplifier. in the 2x3 dfn package, the s gnd and power ground (p gnd ) pins are connected externally. 3.8 power ground pin (p gnd ) the power ground pin is used as a return for the high- current n-channel switch. in the 2x3 dfn package, the p gnd and s gnd pins are connected externally. 3.9 output voltage sense pin (v outs ) the output voltage sense pin connects the regulated output voltage to the internal bias circuits. in the 2x3 dfn package, the v outs and output voltage power (v outp ) pins are connected externally. 3.10 output voltage power pin (v outp ) the output voltage power pin connects the output volt- age to the switch node. high current flows through the integrated p-channel and out of this pin to the output capacitor and output. in the 2x3 dfn package, v outp and v outs are connected externally. 3.11 exposed thermal pad (ep) there is no internal electrical connection between the exposed thermal pad (ep) and the s gnd and p gnd pins. they must be connected to the same potential on the printed circuit board (pcb). pin name mcp1640/b/c/d sot23 mcp1640/b/c/d 2x3 dfn description sw 1 5 switch node, boost inductor input pin gnd 2 ? ground pin en 3 4 enable control input pin fb 4 1 feedback voltage pin v out 5 ? output voltage pin v in 6 8 input voltage pin s gnd ? 2 signal ground pin p gnd ? 3 power ground pin v outs ? 7 output voltage sense pin v outp ? 6 output voltage power pin ep ? 9 exposed thermal pad (ep); must be connected to v ss. mcp1640/b/c/d ds22234b-page 10 ? 2011 microchip technology inc. notes: ? 2011 microchip technology inc. ds22234b-page 11 mcp1640/b/c/d 4.0 detailed description 4.1 device option overview the mcp1640/b/c/d family of devices is capable of low start-up voltage and delivers high efficiency over a wide load range for single cell, two cell, three cell alkaline, nimh, nicd and single cell li-ion battery inputs. a high level of integration lowers total system cost, eases implementation and reduces board area. the devices feature low startup voltage, adjustable out- put voltage, pwm/pfm mode operation, low i q , inte- grated synchronous switch, internal compensation, low noise anti-ring control, inrush current limit, and soft start. there are two feature options for the mcp1640/b/c/d family: ? pwm/pfm mode or pwm-only mode ? ?true output disconnect? mode or input bypass mode 4.1.1 pwm/pfm mode option the mcp1640c devices use an automatic switchover from pwm to pfm mode for light load conditions to maximize efficiency over a wide range of output current. during pfm mode, higher peak current is used to pump the output up to the threshold limit. while operating in pfm or pwm mode, the p-channel switch is used as a synchronous rectifier, turning off when the inductor current reaches 0 ma to maximize efficiency. in pfm mode, a comparator is used to terminate switching when the output voltage reaches the upper threshold limit. once switching has terminated, the output voltage will decay or coast down. during this period, very low i q is consumed from the device and input source, which keeps power efficiency high at light load. the disadvantages of pwm/pfm mode are higher out- put ripple voltage and variable pfm mode frequency. the pfm mode frequency is a function of input voltage, output voltage and load. while in pfm mode, the boost converter pumps the output up at a switching frequency of 500 khz. 4.1.2 pwm-only mode option the mcp1640b/d devices disable pfm mode switching, and operate only in pwm mode over the entire load range. during periods of light load opera- tion, the mcp1640b/d continues to operate at a con- stant 500 khz switching frequency, keeping the output ripple voltage lower than pfm mode. during pwm-only mode, the mcp1640b/d p-channel switch acts as a synchronous rectifier by turning off (to prevent reverse current flow from the output cap back to the input) in order to keep efficiency high. for noise immunity, the n-channel mosfet current sense is blanked for approximately 100 ns. with a typ- ical minimum duty cycle of 100 ns, the mcp1640b/d continues to switch at a constant frequency under light load conditions. figure 2-12 represents the input volt- age versus load current for the pulse skipping threshold in pwm-only mode. at lighter loads, the mcp1640b/d devices begin to skip pulses. 4.1.3 true output disconnect mode option the mcp1640b devices incorporate a true output disconnect feature. with the en pin pulled low, the output of the mcp1640b is isolated or disconnected from the input by turning off the integrated p-channel switch and removing the switch bulk diode connection. this removes the dc path that is typical in boost con- verters, which allows the output to be disconnected from the input. during this mode, less than 1 a of cur- rent is consumed from the input (battery). true output disconnect does not discharge the output, the output voltage is held up by the external c out capacitance. 4.1.4 input bypass mode option the mcp1640c/d devices incorporate the input bypass shutdown option. with the en input pulled low, the output is connected to the input using the internal p-channel mosfet. in this mode, the current draw from the input (battery) is less than 1 a with no load. the input bypass mode is used when the input voltage range is high enough for the load to operate in sleep or low i q mode. when a higher regulated output voltage is necessary to operate the application, the en input is pulled high, enabling the boost converter. table 4-1: part number selection part number pwm/ pfm pwm- only true disconnect input bypass mcp1640 x x mcp1640b x x mcp1640c x x mcp1640d x x mcp1640/b/c/d ds22234b-page 12 ? 2011 microchip technology inc. 4.2 functional description the mcp1640/b/c/d is a compact, high-efficiency, fixed frequency, step-up dc-dc converter that provides an easy-to-use power supply solution for applications powered by either one-cell, two-cell, or three-cell alkaline, nicd, or nimh, or one-cell li-ion or li-polymer batteries. figure 4-1 depicts the functional block diagram of the mcp1640/b/c/d. figure 4-1: mcp1640/b/c/d block diagram. 4.2.1 low-voltage start-up the mcp1640/b/c/d is capable of starting from a low input voltage. start-up voltage is typically 0.65v for a 3.3v output and 1 ma resistive load. when enabled, the internal start-up logic turns the rectifying p-channel switch on until the output capacitor is charged to a value close to the input voltage. the rectifying switch is current-limited during this time. after charging the output capacitor to the input voltage, the device starts switching. if the input voltage is below 1.6v, the device runs open-loop with a fixed duty cycle of 70% until the output reaches 1.6v. during this time, the boost switch current is limited to 50% of its nominal value. once the output voltage reaches 1.6v, normal closed-loop pwm operation is initiated. the mcp1640/b/c/d charges an internal capacitor with a very weak current source. the voltage on this capacitor, in turn, slowly ramps the current limit of the boost switch to its nominal value. the soft-start capacitor is completely discharged in the event of a commanded shutdown or a thermal shutdown. there is no undervoltage lockout feature for the mcp1640/b/c/d. the device will start up at the lowest possible voltage and run down to the lowest possible voltage. for typical battery applications, this may result in ?motor-boating? (emitting a low-frequency tone) for deeply discharged batteries. gate drive and shutdown control logic v in en v out gnd i sense i zero i limit .3v 0v soft-start direction control oscillator slope comp. s pwm/pfm logic 1.21v internal bias sw fb ea ? 2011 microchip technology inc. ds22234b-page 13 mcp1640/b/c/d 4.2.2 pwm-only mode operation in normal pwm operation, the mcp1640/b/c/d operates as a fixed frequency, synchronous boost converter. the switching frequency is internally maintained with a precision oscillator typically set to 500 khz. the mcp1640b/d devices will operate in pwm-only mode even during periods of light load operation. by operating in pwm-only mode, the output ripple remains low and the frequency is constant. operating in fixed pwm mode results in lower efficiency during light load operation (when compared to pfm mode (mcp1640c)). lossless current sensing converts the peak current sig- nal to a voltage to sum with the internal slope compen- sation. this summed signal is compared to the voltage error amplifier output to provide a peak current control command for the pwm signal. the slope compensation is adaptive to the input and output voltage. therefore, the converter provides the proper amount of slope compensation to ensure stability, but is not excessive, which causes a loss of phase margin. the peak current limit is set to 800 ma typical. 4.2.3 pfm mode operation the mcp1640c devices are capable of operating in normal pwm mode and pfm mode to maintain high efficiency at all loads. in pfm mode, the output ripple has a variable frequency component that changes with the input voltage and output current. with no load, the quiescent current draw from the output is typically 19 a. the pfm mode can be disabled in selected device options. pfm operation is initiated if the output load current falls below an internally programmed threshold. the output voltage is continuously monitored. when the output voltage drops below its nominal value, pfm operation pulses one or several times to bring the output back into regulation. if the output load current rises above the upper threshold, the mcp1640c transitions smoothly into pwm mode. 4.2.4 adjustable output voltage the mcp1640/b/c/d output voltage is adjustable with a resistor divider over a 2.0v minimum to 5.5v maximum range. high value resistors are recommended to minimize quiescent current to keep efficiency high at light loads. 4.2.5 enable pin the enable pin is used to turn the boost converter on and off. the enable threshold voltage varies with input voltage. to enable the boost converter, the en voltage level must be greater than 90% of the v in voltage. to disable the boost converter, the en voltage must be less than 20% of the v in voltage. 4.2.6 internal bias the mcp1640/b/c/d gets its start-up bias from v in . once the output exceeds the input, bias comes from the output. therefore, once started, operation is completely independent of v in . operation is only limited by the output power level and the input source series resistance. when started, the output will remain in regulation down to 0.35v typical with 1 ma output current for low source impedance inputs. 4.2.7 internal compensation the error amplifier, with its associated compensation network, completes the closed loop system by comparing the output voltage to a reference at the input of the error amplifier, and feeding the amplified and inverted signal to the control input of the inner current loop. the compensation network provides phase leads and lags at appropriate frequencies to cancel excessive phase lags and leads of the power circuit. all necessary compensation components and slope compensation are integrated. 4.2.8 short circuit protection unlike most boost converters, the mcp1640/b/c/d allows its output to be shorted during normal operation. the internal current limit, and overtemperature protection, limit excessive stress and protect the device during periods of short circuit, overcurrent and over- temperature. while operating in bypass mode, the p-channel current limit is inhibited to minimize quiescent current. 4.2.9 low noise operation the mcp1640/b/c/d integrates a low noise anti-ring switch that damps the oscillations typically observed at the switch node of a boost converter when operating in the discontinuous inductor current mode. this removes the high frequency radiated noise. 4.2.10 overtemperature protection overtemperature protection circuitry is integrated into the mcp1640/b/c/d. this circuitry monitors the device junction temperature and shuts the device off if the junction temperature exceeds the typical +150 o c threshold. if this threshold is exceeded, the device will automatically restart when the junction temperature drops by 10 o c. the soft start is reset during an overtemperature condition. mcp1640/b/c/d ds22234b-page 14 ? 2011 microchip technology inc. notes: ? 2011 microchip technology inc. ds22234b-page 15 mcp1640/b/c/d 5.0 application information 5.1 typical applications the mcp1640/b/c/d synchronous boost regulator operates over a wide input and output voltage range. the power efficiency is high for several decades of load range. output current capability increases with input voltage and decreases with increasing output voltage. the maximum output current is based on the n-chan- nel peak current limit. typical characterization curves in this data sheet are presented to display the typical out- put current capability. 5.2 adjustable output voltage calculations to calculate the resistor divider values for the mcp1640/b/c/d, the following equation can be used. where r top is connected to v out , r bot is connected to gnd and both are connected to the fb input pin. equation 5-1: example a: v out = 3.3v v fb = 1.21v r bot = 309 k ? r top = 533.7 k ? (standard value = 536 k ? ) example b: v out = 5.0v v fb = 1.21v r bot = 309 k ? r top = 967.9 k ? (standard value = 976 k ? ) there are some potential issues with higher value resistors. for small surface mount resistors, environment contamination can create leakage paths that significantly change the resistor divider that effect the output voltage. the fb input leakage current can also impact the divider and change the output voltage tolerance. 5.3 input capacitor selection the boost input current is smoothed by the boost inductor reducing the amount of filtering necessary at the input. some capacitance is recommended to provide decoupling from the source. low esr x5r or x7r are well suited since they have a low temperature coefficient and small size. for most applications, 4.7 f of capacitance is sufficient at the input. for high power applications that have high source impedance or long leads, connecting the battery to the input 10 f of capacitance is recommended. additional input capacitance can be added to provide a stable input voltage. table 5-1 contains the recommended range for the input capacitor value. 5.4 output capacitor selection the output capacitor helps provide a stable output voltage during sudden load transients and reduces the output voltage ripple. as with the input capacitor, x5r and x7r ceramic capacitors are well suited for this application. the mcp1640/b/c/d is internally compensated so output capacitance range is limited. see tab l e 5 - 1 for the recommended output capacitor range. while the n-channel switch is on, the output current is supplied by the output capacitor c out . the amount of output capacitance and equivalent series resistance will have a significant effect on the output ripple voltage. while c out provides load current, a voltage drop also appears across its internal esr that results in ripple voltage. equation 5-2: where dv represents the ripple voltage and dt represents the on time of the n-channel switch (d * 1/ f sw ). table 5-1 contains the recommended range for the input and output capacitor value. r top r bot v out v fb ---------------- 1 ? ?? ?? ?? ? = table 5-1: capacitor value range c in c out min 4.7 f 10 f max none 100 f i out c out dv dt ------ - ?? ?? ? = mcp1640/b/c/d ds22234b-page 16 ? 2011 microchip technology inc. 5.5 inductor selection the mcp1640/b/c/d is designed to be used with small surface mount inductors; the inductance value can range from 2.2 h to 10 h. an inductance value of 4.7 h is recommended to achieve a good balance between inductor size, converter load transient response and minimized noise. several parameters are used to select the correct inductor: maximum rated current, saturation current and copper resistance (esr). for boost converters, the inductor current can be much higher than the output current. the lower the inductor esr, the higher the efficiency of the converter, a common trade-off in size versus efficiency. peak current is the maximum or limit, and saturation current typically specifies a point at which the induc- tance has rolled off a percentage of the rated value. this can range from a 20% to 40% reduction in induc- tance. as inductance rolls off, the inductor ripple cur- rent increases as does the peak switch current. it is important to keep the inductance from rolling off too much, causing switch current to reach the peak limit. 5.6 thermal calculations the mcp1640/b/c/d is available in two different packages, 6-lead sot23 and 8-lead 2x3 dfn. by cal- culating the power dissipation and applying the pack- age thermal resistance, ( ? ja ), the junction temperature is estimated. the maximum continuous junction temperature rating for the mcp1640/b/c/d is +125 o c. to quickly estimate the internal power dissipation for the switching boost regulator, an empirical calculation using measured efficiency can be used. given the measured efficiency, the internal power dissipation is estimated by equation 5-3 . equation 5-3: the difference between the first term ? input power, and the second term ? power delivered, is the internal mcp1640/b/c/d power dissipation. this is an esti- mate, assuming that most of the power lost is internal to the mcp1640/b/c/d and not c in , c out and the inductor. there is some percentage of power lost in the boost inductor, with very little loss in the input and out- put capacitors. for a more accurate estimation of inter- nal power dissipation, subtract the i inrms 2 *l esr power dissipation. 5.7 pcb layout information good printed circuit board layout techniques are important to any switching circuitry; and, switching power supplies are no different. when wiring the switching high current paths, short and wide traces should be used. therefore it is important that the input and output capacitors be placed as close as possible to the mcp1640/b/c/d to minimize the loop area. table 5-2: mcp1640/b/c/d recommended inductors part number value (h) dcr ? (typ) i sat (a) size wxlxh (mm) coilcraft ? epl2014-472 4.7 0.23 1.06 2.0x2.0x1.4 epl3012-472 4.7 0.165 1.1 3.0x3.0x1.3 mss4020-472 4.7 0.115 1.5 4.0x4.0x2.0 lps6225-472 4.7 0.065 3.2 6.0x6.0x2.4 coiltronics ? sd3110 4.7 0.285 0.68 3.1x3.1x1.0 sd3112 4.7 0.246 0.80 3.1x3.1x1.2 sd3114 4.7 0.251 1.14 3.1x3.1x1.4 sd3118 4.7 0.162 1.31 3.8x3.8x1.2 sd3812 4.7 0.256 1.13 3.8x3.8x1.2 sd25 4.7 0.0467 1.83 5.0x5.0x2.5 part number value (h) dcr ? (max) i sat (a) size wxlxh (mm) wurth elektronik ? we-tpc type th 4.7 0.200 0.8 2.8x2.8x1.35 we-tpc type s 4.7 0.105 0.90 3.8x3.8x1.65 we-tpc type m 4.7 0.082 1.65 4.8x4.8x1.8 we-tpc type x 4.7 0.046 2.00 6.8x6.8x2.3 part number value (h) dcr ? (max) i sat (a) size wxlxh (mm) sumida ? cmh23 4.7 0.537 0.70 2.3x2.3x1.0 cmd4d06 4.7 0.216 0.75 3.5x4.3x0.8 cdrh4d 4.7 0.09 0.800 4.6x4.6x1.5 epcos ? b82462a2472 m000 4.7 0.084 2.00 6.0x6.0x2.5 b82462g4472 m 4.7 0.04 1.8 6.3x6.3x3.0 v out i out ? efficiency ------------------------------------- ?? ?? v out i out ? ?? ? p dis = ? 2011 microchip technology inc. ds22234b-page 17 mcp1640/b/c/d the feedback resistors and feedback signal should be routed away from the switching node and the switching current loop. when possible, ground planes and traces should be used to help shield the feedback signal and minimize noise and magnetic interference. figure 5-1: mcp1640/b/c/d sot23-6 recommended layout. figure 5-2: mcp1640/b/c/d dfn-8 recommended layout. c out l c in +v in gnd gnd +v out via to gnd plane mcp1640 via for enable r top r bot 1 c out l c in +v in gnd +v out mcp1640 enable r top r bot gnd wired on bottom plane 1 mcp1640/b/c/d ds22234b-page 18 ? 2011 microchip technology inc. notes: ? 2011 microchip technology inc. ds22234b-page 19 mcp1640/b/c/d 6.0 typical application circuits figure 6-1: manganese lithium coin cell application using bypass mode. figure 6-2: usb on-the-go powered by li-ion. v in gnd v fb sw v out 5.0v @ 5 ma c out 10 f c in 4.7 f l 1 4.7 h v out 976 k ? 309 k ? en manganese lithium dioxide button cell 2.0v to 3.2v + - from pic ? mcu i/o note: for applications that can operate directly from the battery input voltage during sleep mode and require a higher voltage during normal run mode, the mcp1640c device provides input to out- put bypass when disabled. the pic ? microcontroller is powered by the output of the mcp1640c. one of its i/o pins is used to enable and disable the mcp1640c to control its bias voltage. while operating in sleep mode, the mcp1640c input quiescent current is typically less than 1 ua. v in p gnd v fb sw v in 3.3v to 4.2v v out 5.0v @ 350 ma c out 10 f c in 10 f l 1 10 h v outs + - 976 k ? 309 k ? v outp s gnd li-ion en mcp1640/b/c/d ds22234b-page 20 ? 2011 microchip technology inc. notes: ? 2011 microchip technology inc. ds22234b-page 21 mcp1640/b/c/d 7.0 packaging information 7.1 package marking information (not to scale) legend: xx...x customer-specific information y year code (last digit of calendar year) yy year code (last 2 digits of calendar year) ww week code (week of january 1 is week ?01?) nnn alphanumeric traceability code pb-free jedec designator for matte tin (sn) * this package is pb-free. the pb-free jedec designator ( ) can be found on the outer packaging for this package. note : in the event the full microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. 3 e 3 e 6-lead sot-23 xxnn example bznn xxx 8-lead dfn yww nn ahm example 945 25 package marking mcp1640 bznn mcp1640c bxnn mcp1640b bwnn mcp1640d bynn package marking mcp1640 ahm mcp1640c ahq mcp1640c ahp mcp1640d ahr mcp1640/b/c/d ds22234b-page 22 ? 2011 microchip technology inc. !! "# "$%" "& ! $%!! "& ! $%!!! $ ' " !" ! "$ #( ) *+, * ! ! $ ' $- % !..$%$$ ! /$ !$% $ 0 " . !1 ! ! $ 2 0 & $ $ " $ $$ ,33... 3 0 4$! 55 ## !5 $! 6 67 8 6% 9 &2! 6 2$ )*+ 7%$!" 5 "2$ *+ 7- : $ ; ) " "2 0 0 !! < ; $ "&& ; ) 7- ="$ # ; " "2 0 ="$ # ; < 7- 5 $ ; /$5 $ 5 ; /$ $ 5 ) ; < /$ > ; > 5 "0 !! < ; 5 "="$ 9 ; ) b e 4 n e1 pin1idby laser mark d 1 2 3 e e1 a a1 a2 c l l1 . + <* ? 2011 microchip technology inc. ds22234b-page 23 mcp1640/b/c/d note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging mcp1640/b/c/d ds22234b-page 24 ? 2011 microchip technology inc. ! " # $ %&'( ) )*+,-."# 2 -!% " '& $% - 19%$ %!$9 $ ".$$ $ " 2 0 - ' ! "$ 9 ! $ "! 2 0 !! .! % $ " ! "$ #( ) *+, * ! ! $ ' $- % !..$%$$ ! #/, & !1%!% .$%$$ 1&& $ % ! ! /$ !$% $ 0 " . !1 ! ! $ 2 0 & $ $ " $ $$ ,33... 3 0 4$! 55 ## !5 $! 6 67 8 6% 9 &2! 6 < 2$ )*+ 7- : $ < $ "&& ) +$ $0 !! #/ 7- 5 $ *+ 7- ="$ # *+ #' ! "2 "5 $ ; )) #' ! "2 "="$ # ) ; ) +$ $="$ 9 ) +$ $5 $ 5 ) +$ $ $ #' ! "2 " ? ; ; d n e note 1 1 2 exposed pad note 1 2 1 d2 k l e2 n e b a3 a1 a note 2 bottom view top view . + + ? 2011 microchip technology inc. ds22234b-page 25 mcp1640/b/c/d note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging mcp1640/b/c/d ds22234b-page 26 ? 2011 microchip technology inc. notes: ? 2011 microchip technology inc. ds22234b-page 27 mcp1640/b/c/d appendix a: revision history revision b (march 2011) the following is the list of modifications: 1. updated ta b l e 5 - 2 . 2. added the package markings tables in section 7.0 ?packaging information? . revision a (february 2010) original release of this document. mcp1640/b/c/d ds22234b-page 28 ? 2011 microchip technology inc. notes: ? 2011 microchip technology inc. ds22234b-page 29 mcp1640/b/c/d product identification system to order or obtain information, e.g., on pricing or delivery, contact your loca l microchip representative or sales office . examples: a) mcp1640-i/mc: 0.65v, sync reg., 8ld-dfn pkg. b) mcp1640t-i/mc: tape and reel, 0.65v, sync reg., 8ld-dfn pkg. c) mcp1640b-i/mc: 0.65v, sync reg., 8ld-dfn pkg. d) mcp1640bt-i/mc: tape and reel, 0.65v, sync reg., 8ld-dfn pkg. e) mcp1640c-i/mc: 0.65v, sync reg., 8ld-dfn pkg. f) mcp1640ct-i/mc: tape and reel, 0.65v, sync reg., 8ld-dfn pkg. g) mcp1640d-i/mc: 0.65v, sync reg., 8ld-dfn pkg. h) mcp1640dt-i/mc: tape and reel, 0.65v, sync reg., 8ld-dfn pkg. i) mcp1640t-i/chy: tape and reel, 0.65v, sync reg., 6ld sot-23 pkg. j) mcp1640bt-i/chy: tape and reel, 0.65v, sync reg., 6ld sot-23 pkg. k) mcp1640ct-i/chy: tape and reel, 0.65v, sync reg., 6ld sot-23 pkg. l) mcp1640dt-i/chy: tape and reel, 0.65v, sync reg., 6ld sot-23 pkg. part no. x /xx package temperature range device device mcp1640: 0.65v, pwm/pfm true disconnect, sync boost regulator mcp1640t: 0.65v, pwm/pfm true disconnect, sync boost regulator (tape and reel) mcp1640b: 0.65v, pwm only true disconnect, sync boost regulator mcp1640bt: 0.65v, pwm only true disconnect, sync boost regulator (tape and reel) mcp1640c: 0.65v, pwm/pfm input to output bypass, sync boost regulator mcp1640ct: 0.65v, pwm/pfm input to output bypass, sync boost regulator (tape and reel) mcp1640d: 0.65v, pwm only input to output bypass, sync boost regulator mcp1640dt: 0.65v, pwm only input to output bypass, sync boost regulator (tape and reel) temperature range i = -40 ? c to +85 ? c (industrial) package ch = plastic small outline transistor (sot-23), 6-lead mc = plastic dual flat, no lead (2x3 dfn), 8-lead x tape and reel mcp1640/b/c/d ds22234b-page 30 ? 2011 microchip technology inc. notes: ? 2011 microchip technology inc. ds22234b-page 31 information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. it is your responsibility to ensure that your application meets with your specifications. microchip makes no representations or warranties of any kind whether express or implied, written or oral, statutory or otherwise, related to the information, including but not limited to its condition, quality, performance, merchantability or fitness for purpose . microchip disclaims all liability arising from this information and its use. use of microchip devices in life support and/or safety applications is entirely at the buyer?s risk, and the buyer agrees to defend, indemnify and hold harmless microchip from any and all damages, claims, suits, or expenses resulting from such use. no licenses are conveyed, implicitly or otherwise, under any microchip intellectual property rights. trademarks the microchip name and logo, the microchip logo, dspic, k ee l oq , k ee l oq logo, mplab, pic, picmicro, picstart, pic 32 logo, rfpic and uni/o are registered trademarks of microchip technology incorporated in the u.s.a. and other countries. filterlab, hampshire, hi-tech c, linear active thermistor, mxdev, mxlab, seeval and the embedded control solutions company are registered trademarks of microchip technology incorporated in the u.s.a. analog-for-the-digital age, appl ication maestro, codeguard, dspicdem, dspicdem.net, dspicworks, dsspeak, ecan, economonitor, fansense, hi-tide, in-circuit serial programming, icsp, mindi, miwi, mpasm, mplab certified logo, mplib, mplink, mtouch, omniscient code generation, picc, picc-18, picdem, picdem.net, pickit, pictail, real ice, rflab, select mode, total endurance, tsharc, uniwindriver, wiperlock and zena are trademarks of microchip tec hnology incorporated in the u.s.a. and other countries. sqtp is a service mark of microchip technology incorporated in the u.s.a. all other trademarks mentioned herein are property of their respective companies. ? 2011, microchip technology incorporated, printed in the u.s.a., all rights reserved. printed on recycled paper. isbn: 978-1-60932-829-0 note the following details of the code protection feature on microchip devices: ? microchip products meet the specification cont ained in their particular microchip data sheet. ? microchip believes that its family of products is one of the most secure families of its kind on the market today, when used i n the intended manner and under normal conditions. ? there are dishonest and possibly illegal methods used to breach the code protection feature. all of these methods, to our knowledge, require using the microchip produc ts in a manner outside the operating specif ications contained in microchip?s data sheets. most likely, the person doing so is engaged in theft of intellectual property. ? microchip is willing to work with the customer who is concerned about the integrity of their code. ? neither microchip nor any other semiconduc tor manufacturer can guarantee the security of their code. code protection does not mean that we are guaranteeing the product as ?unbreakable.? code protection is constantly evolving. we at microchip are co mmitted to continuously improvin g the code protection features of our products. attempts to break microchip?s code protection feature may be a violation of the digital millennium copyright act. if such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that act. microchip received iso/ts-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona; gresham, oregon and design centers in california and india. the company?s quality system processes and procedures are for its pic ? mcus and dspic ? dscs, k ee l oq ? code hopping devices, serial eeproms, microperipherals, nonvolatile memory and analog products. in addition, microchip?s quality system for the design and manufacture of development systems is iso 9001:2000 certified. ds22234b-page 32 ? 2011 microchip technology inc. americas corporate office 2355 west chandler blvd. chandler, az 85224-6199 tel: 480-792-7200 fax: 480-792-7277 technical support: http://www.microchip.com/ support web address: www.microchip.com atlanta duluth, ga tel: 678-957-9614 fax: 678-957-1455 boston westborough, ma tel: 774-760-0087 fax: 774-760-0088 chicago itasca, il tel: 630-285-0071 fax: 630-285-0075 cleveland independence, oh tel: 216-447-0464 fax: 216-447-0643 dallas addison, tx tel: 972-818-7423 fax: 972-818-2924 detroit farmington hills, mi tel: 248-538-2250 fax: 248-538-2260 indianapolis noblesville, in tel: 317-773-8323 fax: 317-773-5453 los angeles mission viejo, ca tel: 949-462-9523 fax: 949-462-9608 santa clara santa clara, ca tel: 408-961-6444 fax: 408-961-6445 toronto mississauga, ontario, canada tel: 905-673-0699 fax: 905-673-6509 asia/pacific asia pacific office suites 3707-14, 37th floor tower 6, the gateway harbour city, kowloon hong kong tel: 852-2401-1200 fax: 852-2401-3431 australia - sydney tel: 61-2-9868-6733 fax: 61-2-9868-6755 china - beijing tel: 86-10-8528-2100 fax: 86-10-8528-2104 china - chengdu tel: 86-28-8665-5511 fax: 86-28-8665-7889 china - chongqing tel: 86-23-8980-9588 fax: 86-23-8980-9500 china - hong kong sar tel: 852-2401-1200 fax: 852-2401-3431 china - nanjing tel: 86-25-8473-2460 fax: 86-25-8473-2470 china - qingdao tel: 86-532-8502-7355 fax: 86-532-8502-7205 china - shanghai tel: 86-21-5407-5533 fax: 86-21-5407-5066 china - shenyang tel: 86-24-2334-2829 fax: 86-24-2334-2393 china - shenzhen tel: 86-755-8203-2660 fax: 86-755-8203-1760 china - wuhan tel: 86-27-5980-5300 fax: 86-27-5980-5118 china - xian tel: 86-29-8833-7252 fax: 86-29-8833-7256 china - xiamen tel: 86-592-2388138 fax: 86-592-2388130 china - zhuhai tel: 86-756-3210040 fax: 86-756-3210049 asia/pacific india - bangalore tel: 91-80-3090-4444 fax: 91-80-3090-4123 india - new delhi tel: 91-11-4160-8631 fax: 91-11-4160-8632 india - pune tel: 91-20-2566-1512 fax: 91-20-2566-1513 japan - yokohama tel: 81-45-471- 6166 fax: 81-45-471-6122 korea - daegu tel: 82-53-744-4301 fax: 82-53-744-4302 korea - seoul tel: 82-2-554-7200 fax: 82-2-558-5932 or 82-2-558-5934 malaysia - kuala lumpur tel: 60-3-6201-9857 fax: 60-3-6201-9859 malaysia - penang tel: 60-4-227-8870 fax: 60-4-227-4068 philippines - manila tel: 63-2-634-9065 fax: 63-2-634-9069 singapore tel: 65-6334-8870 fax: 65-6334-8850 taiwan - hsin chu tel: 886-3-6578-300 fax: 886-3-6578-370 taiwan - kaohsiung tel: 886-7-213-7830 fax: 886-7-330-9305 taiwan - taipei tel: 886-2-2500-6610 fax: 886-2-2508-0102 thailand - bangkok tel: 66-2-694-1351 fax: 66-2-694-1350 europe austria - wels tel: 43-7242-2244-39 fax: 43-7242-2244-393 denmark - copenhagen tel: 45-4450-2828 fax: 45-4485-2829 france - paris tel: 33-1-69-53-63-20 fax: 33-1-69-30-90-79 germany - munich tel: 49-89-627-144-0 fax: 49-89-627-144-44 italy - milan tel: 39-0331-742611 fax: 39-0331-466781 netherlands - drunen tel: 31-416-690399 fax: 31-416-690340 spain - madrid tel: 34-91-708-08-90 fax: 34-91-708-08-91 uk - wokingham tel: 44-118-921-5869 fax: 44-118-921-5820 worldwide sales and service 02/18/11 |
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