G5644 Global Mixed-mode Technology Inc. 2.5A Buck Converter General Description Features The G5644 is a high efficiency, 2.5A buck converter with a high-side low RDS(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 consumption. Hence it is suitable for battery-powered devices. 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 It uses a fixed switching frequency up to 500kHz. When a short circuit is detected on the output, the device change switching frequency to 50kHz to protect IC from damage. Applications The G5644 is available in a SOP-8 package. Distributed Power Systems Battery Charger Palmtop Computers, PDAs DSL Modems 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 G5644 V IN 5 V~18V G5644 IN 1 8 NC EN 2 7 LX COMP 3 6 GND FB 4 5 NC C C2 optional 4.7µH LX IN 10µF OFF ON EN COMP CC GND 1.5nF RC 20kΩ D1 SS34 FB SOP-8 C C2 10pF IN 10µF EN OFF ON CO MP CC GND 470pF 47µF MLCC R2/12kΩ G5644 V IN 5 V~18V R1/3kΩ VOUT 1V/2.5A 4.7µH LX D1 SS34 R1/3kΩ FB R2/12kΩ VOUT 1V/2.5A 0.1µF 100µF/220µF Electr olytic RC 60kΩ V OUT = 0.8V x ( 1 + R1 R2 ) TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 0.1 Sep 05, 2008 1