esmt/emp preliminary EML3230 elite semiconductor memory technology inc./elite micropower inc. publication date : nov. 2011 revision : 0.2 1/15 3a, 23v, 340khz synchronous step-down converter general description the EML3230 is a synchronous step-down dc/dc converter that provides wide 4.5v to 23v input voltage range and 3a continuous load current capability. fault protection includes cy cle-by-cycle current limit, input uvlo, output over voltage protection and thermal shutdown. besides, adjustable soft-start function prevents inrush current at turn-on. this device uses current mode control scheme that provides fast transient re sponse. in shutdown mode, the supply current is about 10ua. the EML3230 is available in an 8-pin sop package, provides a very compact system solution and good thermal conductance. features ? wide input voltage from 4.5v to 23v ? 3a output current ? adjustable output voltage from 0.925v to 20v ? 100m ? integrated power mosfet ? high efficiency up to 93% ? fixed 340khz switching frequency ? current mode operation ? adjustable soft-start ? cycle-by-cycle current limit ? input under voltage lockout ? over-temperature protection ? 10ua shutdown current ? thermal enhanced sop-8 package ? rohs compliant applications ? set-top-box ? dvd, lcd displays ? olpc, netbook ? distributed power system ? datacom, xdsl typical application fig. 1
esmt/emp preliminary EML3230 elite semiconductor memory technology inc./elite micropower inc. publication date : nov. 2011 revision : 0.2 2/15 package configuration bs ss 1 in 2 sw 3 gnd 4 9 gnd 8 en 7 comp 6 fb 5 e-sop-8l EML3230-00se08nrr 00 adjustable se08 e-sop-8l package nrr rohs & halogen free package commercial grade temperature rating: -40 to 85c package in tape & reel order, mark & packing information package vout(v) product id marking packing e-sop-8l adjustable EML3230-00sg08nrr tape & reel 3k units functional block diagram fig. 2
esmt/emp preliminary EML3230 elite semiconductor memory technology inc./elite micropower inc. publication date : nov. 2011 revision : 0.2 3/15 pin functions pin name e-sop-8l function bs 1 bootstrap. a 10nf or greater capacitor must be connected from this pin to sw. it can boost the gate drive to fully turn on the internal high side nmos. in 2 power input pin. drive 4.5v to 23v voltage to this pin to power on this chip. connecting a 10uf ceramic bypass capacitor between v in and gnd to eliminate noise. sw 3 switch pin. must be connected to inductor. this pin connects to the drains of the internal main and synchronous power mosfet switches. gnd 4 ground pin. fb 5 feedback pin. receives the feedback voltage from an external resistive divider across the output, it regulates at 0.925v. comp 6 compensation. this pin is used to compensate the regulation control loop. connect a series rd network from comp pin to gnd. en 7 enable pin. this pin provides a digital control to turn the converter on or off. connect to v in with a 100k ? resistor for self-startup. ss 8 soft-start. this pin controls the soft-start period. connect a capacitor from ss to gnd to set the soft start period. to disable the soft-start feature, leave ss unconnected. exposed pad 9 thermal pad. connect to gnd.
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