ver:0.92 aug 05, 2013 tel: 886-3-5788833 http://www.gmt.com.tw 1 g5798/g5798a g5799/G5799A global mixed-mode technology 500khz 2a/3a synchronous step-down dc/dc features ? 2a/3a output current ? internal 100m rds-on high-side and 100m rds-on low-side power switches ? available two kinds of delay in pg pg pin is detect fb until threshold then immediately react in g579x pg pin is detect fb until threshold then delay 220ms react in g579xa ? stable with low esr output ceramic capaci- tors ? 32a shutdown mode ? fixed 500khz frequency ? thermal shutdown ? cycle-by-cycle over current protection ? wide 4.5v to 24v operating input range ? vref =0.8v +-2% ? internal soft start ? available in sop-8/sop-8 (fd) package applications ? dsl modems ? distributed power systems ? pre-regulator for linear regulators general description the g5798/g5799 is a monolit hic step-down switch mode regulator with a built in internal power mosfet. it achieves 2a/3a continuous output current over a wide input supply range with excellent load and line regulation. current mode operation provides fast transient response and eases loop stabilization. fault condition protection includes cycle-by-cycle current limiting, output short circui t protection and thermal shut- down. in shutdown mode the regulator draws 32a of supply current. internal soft-start for output power up ramp and minimizes the inrush supply current at initial startup. pg in g579x is open-drai n pin detect from fb. when fb>0.92xvref, pg is high impedance and fb<0.85xvref, pg is low impedance. g579xa add typical 220ms deglitch timeout period when fb>0.92xvref to ma ke sure pg signal. the g5798/g5799 requires a minimum number of readily available standard external co mponents. it is available in a sop-8 (fd) package. ordering information order number marking pg delay time temp. range package (green) g5798p11u g5798 no delay -40c to +85c sop-8 g5798ap11u g5798a delay 220ms -40c to +85c sop-8 g5799f11u g5799 no delay -40c to +85c sop-8 (fd) G5799Af11u G5799A delay 220ms -40c to +85c sop-8 (fd) note: p1: sop-8 f1: sop-8 (fd) 1: bonding code u : tape & reel pin configuration gnd sw 8 6 5 1 2 3 4 bst in vcc pg en fb sop-8 g5798/g5798a 7 gnd 8 6 5 1 2 3 4 sop-8 (fd) g5799/G5799A 7 note: recommend connecting the thermal pad to the ground for excellent power dissipation. thermal pad sw bst in vcc pg en fb gnd sw 8 6 5 1 2 3 4 bst in vcc pg en fb sop-8 g5798/g5798a 7 gnd 8 6 5 1 2 3 4 sop-8 (fd) g5799/G5799A 7 note: recommend connecting the thermal pad to the ground for excellent power dissipation. thermal pad sw bst in vcc pg en fb
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