ver: 0.1 sep 05, 2008 tel: 886-3-5788833 http://www.gmt.com.tw 1 G5644 global mixed-mode technology inc. 2.5a 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 ? 2.5a output current ? 0.8v internal reference ? shutdown control ? thermal-shutdown and internal soft start ? cycle-by-cycle current-limit ? short circuit protection ? under-voltage lockout protection ? sop-8 package applications ? distributed power systems ? battery charger ? palmtop computers, pdas ? dsl modems general description the G5644 is a high efficiency, 2.5a 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 2.5a continuous output current with the output voltage adjustable down to 0.8v. whenever the load is light, the G5644 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 G5644 is available in a sop-8 package. ordering information order number marking temp. range package (pb free) G5644p11u G5644 -40 c to +85 c sop-8 note: p1: sop-8 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 G5644 7 en comp fb lx gnd v in 5v~18v d1 ss 34 4.7 h r1/3k r2/12k c c2 optio nal in c c 1.5nf 47 f mlcc v out 1v/2.5a 10 f r c 20k G5644 on off v out = 0.8v x ( 1 + ) r1 r2 en comp fb lx gnd d1 ss 34 4.7 h r1/3k r2/12k in 0.1 f v out 1v/2.5a G5644 100 f/220 f ele ctr olytic v in 5v~18v c c2 10pf c c 47 0pf 10 f r c 60k on off comp 8 6 5 1 2 3 4 in en fb nc lx gnd nc sop-8 G5644 7 en comp fb lx gnd v in 5v~18v d1 ss 34 4.7 h r1/3k r2/12k c c2 optio nal in c c 1.5nf 47 f mlcc v out 1v/2.5a 10 f r c 20k G5644 on off on off v out = 0.8v x ( 1 + ) r1 r2 en comp fb lx gnd d1 ss 34 4.7 h r1/3k r2/12k in 0.1 f v out 1v/2.5a G5644 100 f/220 f ele ctr olytic v in 5v~18v c c2 10pf c c 47 0pf 10 f r c 60k on off on off
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