ver: 0.9 mar 06, 2012 tel: 886-3-5788833 http://www.gmt.com.tw 1 G5642 global mixed-mode technology 3a buck converter features ? 4.75v to 20v supply voltage operating range ? fixed 500khz switching frequency ? current-mode buck pwm converter ? built-in p-channel power mosfet ? 3a output current ? 1.2v internal reference ? shutdown control ? thermal-shutdown and internal soft start ? cycle-by-cycle current-limit ? short circuit protection ? under-voltage lockout protection ? rohs compliant ? sop-8 (fd) package applications ? distributed power systems ? battery charger ? palmtop computers, pdas ? dsl modems general description the G5642 is a high efficiency, 3a buck converter with a high-side low r ds(on) switch. it operates from 4.75v to 20v input voltage range, and provides up to 3a con- tinuous output current with the output voltage adjust- able down to 1.2v. whenever the load is light, the G5642 automatically change the pwm operation mode to pfm operation to minimize the power con- sumption. hence it is suitable for battery-powered de- vices. it uses a fixed switching frequency up to 500khz. when a short circuit is detected on the output, the de- vice change switching frequency to 50khz to protect ic from damage. the G5642 is available in a sop-8 (fd) package. ordering information order number marking temp. range package (green) G5642f11u G5642 -40 c to +85 c sop-8 (fd) note: f1: sop-8 (fd) 1: bonding code u : tape & reel pin configuration typical application circuit comp 8 6 5 1 2 3 4 in en fb nc lx gnd nc sop-8 (fd) G5642 7 thermal pad en comp fb lx gnd v in 5v~18v d1 ss34 l r1 r2 c c2 optional in c c c out mlcc v out 10 f r c G5642 on off v out = 1.2v x ( 1 + ) r1 r2 en comp fb lx gnd d1 ss34 l r1 r2 in 0.1 f v out G5642 c out electrolytic v in 5v~18v c c2 optional c c 10 f r c on off * refer to table 1 & table 2 for component selection comp 8 6 5 1 2 3 4 in en fb nc lx gnd nc sop-8 (fd) G5642 7 thermal pad en comp fb lx gnd v in 5v~18v d1 ss34 l r1 r2 c c2 optional in c c c out mlcc v out 10 f r c G5642 on off on off v out = 1.2v x ( 1 + ) r1 r2 en comp fb lx gnd d1 ss34 l r1 r2 in 0.1 f v out G5642 c out electrolytic v in 5v~18v c c2 optional c c 10 f r c on off on off * refer to table 1 & table 2 for component selection
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