general description the AMS34063 is a monolithic control circuit containing the pr imary functions required for dc/dc converters. the device consists of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver and high current output switch. this device is specifically designed to be incorporated in step-down, step-up and voltage-inverting applications with a minimum number of external components. the 2% internal reference and low quiescent current of 1.6ma are among the improvements of the device over the competition features ? 3v to 40v input v oltage operation. ? internal 1.5a peak current switch. ? internal 2% reference. ? low quiescent current . ? frequency operation up to 100khz. ? low dropout operation: 100% duty cycle ? current limiting. ? standard dip8 and sop8 packages applications ? dc-dc converter module ? adsl modems ? hub. ? battery chargers functional diagram
pin des c ription symbol pin no. description sc 1 1.5a switch collector se 2 darlington switch emitter tc 3 oscillator timing capacitor gnd 4 power gnd fb 5 feedback comparat or inverting input vcc 6 power supply input ipk 7 highside current sense input, vcc - vipk=300mv dri 8 drive collector ordering information orderi ng num ber package AMS34063 sop8 AMS34063a dip8 absolute maximum ratings supply voltage ??????.????????. ????????????? ??40v comparator input voltage range ?????????.??..?????????-0.3v~40v switch collector voltage ????????????????????????. 40v switch emitter voltage ?????????????????????????? 40v switch collector to emitter voltage ????????????????????.. .40v driver collector voltage ??????????????????????????.40v switch current??????????????????????????????..1.5a power dissipation and thermal characteristics dip package ta= 25c??????????????????????..1.0w thermal resistance ??????????????...... 100c /w so package ta= 25c ????????????????????625mw thermal resistance ???????????????...160c /w operating junction temperature ???..???????????????????125c operating ambient temperature range ??...??????????????.. 0c~70c storage temperature range ?????....??????????????... - 65c~150c
electrical characteristics (vcc= 5v, ta=25c (unless otherwise specified.) parameter test condictions symbol min. typ. max. unit oscillator frequency v pin5 = 0v ,c t = 1nf f osc 24 35 46 kh z charging current 5.0v~vcc~40v i chg 24 35 46 a discharge current 5.0v~vcc~40v i dischg 140 220 260 a voltage swing pin 3 v osc 0.6 v discharge to charge current ratio v ipk(sense) =vcc i dischg/ i chg 6.0 current limit sense voltage i chg = i dischg v ipk(sense) 250 320 400 mv output switch saturation voltage, darlington connection i sw =1.0a; v c(driver) = v c(switch) v ce(sat) 1.0 1.3 v saturation voltage i sw =1.0a; i c(driver) = 50ma (forced ?=20) v ce (sat) 0.45 0.7 v dc current gain i sw =1.0a; v ce =5.0v h fe 50 75 collector off-state current v ce =40v i c(off) 10 na comparator threshold voltage threshold voltage 0c~ta~70c v fb 1.225 1.25 1.275 1.19 1.31 v v threshold voltage line re g ulation 3.0v~vcc~40v regline 0.1 0.3 mv/v input bias current vin=0v iib 0.4 1 a supply current vipk(sense)=vcc vpin 5>vfb 5.0v~vcc~40v ct=0.001f, pin 2=gnd icc 4 ma
typical performance characteristics
application information design formula table
application examples line regulation v in = 10v ~20v @ i o =500ma 40mv load regulation v in = 15v, @ i o =10ma ~ 500m a 5mv short circuit current v in =15v, @ r l = 0.1 1.3a fig.1 step-down converter fig.2 step-down converter with ex ternal pnp saturation switch
application examples (continued) line regulation v in = 8v ~16v @ i o =180ma 50mv load regulation v in = 12v, @ i o =80ma ~ 180ma 10mv fig.3 step-up converter fig.4 step-up converter with external npn switch
application examples (continued) line regulation v in =4.5v~6v @i o =100ma 20mv load regulation v in =4.5v~6v @i o =100ma 100mv fig.5 lnverting converter fig 6. voltage lnverting converter with pnp saturated switch
package description sop8 package outl ine dimensions
dip8 package outl ine dimensions
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