FAN5308

FAN5308 — 800mA High-Efficiency Step-Down DC-DC Converter June 2007 FAN5308 tm 800mA High-Efficiency Step-Down DC-DC Converter Features ■ 96% efficiency, synchronous operation ■ Adjustable output voltage options from 0.8V to VIN ■ 2.5V to 5.5V input voltage range ■ Up to 800mA output current ■ Fixed-frequency 1.3MHz PWM operation ■ High-efficiency, power-save mode ■ 100% duty cycle low-dropout operation ■ Soft-start ■ Output over-voltage protection ■ Dynamic output voltage positioning ■ 25µA quiescent current ■ Thermal shutdown and short-circuit protection ■ Pb-free 3x3mm 6-lead MLP package Applications ■ Pocket PCs, PDAs ■ Cell phones ■ Battery-powered portable devices ■ Digital cameras ■ Hard disk drives ■ Set-top boxes ■ Point-of-load power ■ Notebook computers ■ Communications equipment Description Designed for use in battery-powered applications, the FAN5308 is a high-efficiency, low-noise synchronous PWM current mode and pulse skip (power-save) mode DC-DC converter. It can provide up to 800mA of output current over an input range from 2.5V to 5.5V. The output voltage can be externally adjusted over a range of 0.8V to 5.5V by means of an external voltage divider. At moderate and light loads, pulse skipping modulation is used. Dynamic voltage positioning is applied and the output voltage is shifted 0.8% above nominal value for increased headroom during load transients. At higher loads, the system automatically switches over to current mode PWM control, operating at 1.3...