general description the max8857a pmic provides a complete power-sup- ply solution for digital still cameras (dscs) and digital video cameras (dvcs). the max8857a improves per- formance, component count, and board space utiliza- tion compared to currently available solutions for 2 aa cell and dual-battery designs. on-chip power mosfets provide up to 95% efficiency for critical power supplies. the ccd inverter can operate directly from 2 aa/nimh batteries without the use of any addi- tional external components. step-up synchronous-rectified dc-dc converter (su). the max8857a is bootstrapped from v su . main synchronous-rectified step-up dc-dc converter (m) with active discharge for dsp i/o supply voltage. sdz synchronous-rectified step-down dc-dc con- verter (z) for dsp ddr supply voltage. low-voltage (down to 1v) synchronous-rectified step-down dc-dc converter (sd) for dsp core sup- ply voltage. step-up dc-dc converter with current regulation and pwm dimming control (ledbst) for up to 6 series white leds (wled). high-voltage step-up dc-dc converter (ccdbst) for ccd imagers or positive lcd bias supplies. transformerless inverting dc-dc converter (ccdinv) for ccd imagers or negative lcd bias supplies. this converter can connect directly to 2 aa batteries. the max8857a has an independent/simultaneous power-on sequence of the ccdbst and ccdinv con- verters. for a preset power-on sequence of ccdbst before ccdinv, contact the factory. the max8857a is available in a 5mm x 5mm, 40-pin thin qfn package and operates over the -40? to +85? extended temperature range. applications dscs and dvcs pdas and portable media players features 95% efficient synchronous-rectified dc-dc converters 90% efficient boost-buck operation up to 85% efficient, high-voltage dc-dc converters inverter operates directly from 2 aa batteries internal compensation on all channels true shutdown on all step-up converters overload protection startup into short protection soft-start for controlled startup current 100% duty cycle on step-down converters regulated current output for up to 6 white leds pwm dimming of wled current adjustable led overvoltage protection up to 27v transformerless inverting converter for ccd 2mhz ?.5% switching frequency 1? shutdown supply current ccd voltage sequencing all internal power mosfets sdok power-ok indicator max8857a smallest, all-internal mosfet, 7-channel 2 aa dsc pmic ________________________________________________________________ maxim integrated products 1 pvbst su step-up onsu main step-up sdz step-down ledbst ccdbst ccdinv onm onsd onled onbst oninv onz sd step-down v su 5v v main 3.3v v sd 1.8v v ddrz 2.5v v ledbst up to 6 wleds v ccdbst +15v v ccdinv -7.5v input 1.8v to 5.5v sdok max8857a typical operating circuit 19-0987; rev 1; 2/12 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. pin configuration appears at the end of data sheet. evaluation kit available true shutdown is a trademark of maxim integrated products, inc. ordering information part temp range pin-package pkg code max8857aetl+ -40 c to +85 c 40 thin qfn-ep* 5mm x 5mm x 0.8mm t4055-2 max8857aetl+ tcbr -40 c to +85 c 40 thin qfn-ep* 5mm x 5mm x 0.8mm t4055-2 + denotes a lead-free package. * ep = exposed paddle. note: contact factory for the option where ccdbst must reach regulation before the inv converter can be turned on. abridged
max8857a smallest, all-internal mosfet, 7-channel 2 aa dsc pmic 14 ______________________________________________________________________________________ lxsu pvsu su fbsu pgsu (ep) pgsd (ep) pgm (ep) pvm v batt v su (5v, 500ma) lxm fbm v main (3.3v, 300ma) pvsd lxsd fbsd onsu note 1: all on_ pins have internal 1m ? pulldown to ground. note 2: all converters? power ground connections are through the exposed paddle (ep). onm onled onbst oninv lxinv fbinv swbst lxbst fbbst pvled swled lxled ovled fbled pgbst (ep) pgled (ep) ep gnd ref pvinv v batt v batt (1.8v to 5.5v) v ccdbst (15v, 30ma) v ledbst (16v, 25ma) v ccdinv (-7.5v, 100ma) onsd pvbst c20 0.1f c18 1f l2 1h c1 22f c2 22f l1 2h l6 2.2h l7 10h d1 d2 d3 c5 1f 24 32 30 26 27 39, 40 1, 2 3 35 7 34 28 4 33 12 21 8 25 9 11 10 14 13 18 22 20 17 23 15 16 29 lxsu 31 pvsu 37 lxz 6 r16 100k? v batt onz 38 pgz (ep) fbz 5 pvz 36 d7 d6 d5 d4 max8857a c3 22f c4 22f c21 0.1f r17 100? r2 100k? r3 23.2k? r1 402k? c6 22f c7 22f v batt c8 10f v su c11 1f v batt c14 1f v batt v ref c16 1f r4 10k? v sd (1.8v, 250ma) l3 4.7h r5 80.6k? c10 10f c9 10f r6 100k? v ddrz (2.5v, 200ma) l4 4.7h l5 4.7h r7 150k? c12 10f c13 10f c15 3.3f r8 100k? r9 1.6m? r10 100k? c17 2.2f c19 10f r11 1.4m? r12 100k? r13 604k? r14 100k? sdok r15 10? v batt v su pvgd 19 v su c23 1 f, optional v ref figure 1. max8857a typical application circuit abridged
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