SG1577A

SG1577A — Dual Synchronous DC/DC Controller September 2009 SG1577A Dual Synchronous DC/DC Controller Features ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ Integrated Two Sets of MOSFET Drivers Two Independent PWM Controllers Constant Frequency Operation: Free-running Fixed Frequency Oscillator Programmable: 61kHz to 340kHz Maximum Input Supply Voltage: 15V Programmable Output as Low as 0.7V Internal Error Amplifier Reference Voltage: 0.7V±1.5% Two Soft-Start / EN Functions Programmable Over-Current Protection (OCP) 30V HIGH Voltage Pin for Bootstrap Voltage Output Over-Voltage Protection (OVP) 20-Pin SOP Description The SG1577A is a high-efficiency, voltage-mode, dualchannel, synchronous DC/DC PWM controller for two independent outputs. The two channels are operated out of phase. The internal reference voltage is trimmed to 0.7V±1.5%. It is connected to the error amplifier’s positive terminal for voltage feedback regulation. The soft-start circuit ensures the output voltage can be gradually and smoothly increased from zero to its final regulated value. The soft-start pin can also be used for chip-enable function. When two soft-start pins are grounded, the chip is disabled and the total operation current can be reduced to under 0.7mA. The fixed-frequency is programmable from 60kHz to 340kHz. The Over-Current Protection (OCP) level can be programmed by an external current sense resistor. It has two integrated sets of internal MOSFET drivers. SG1577A is available in a 20-pin SOP package. Applicati...