S-8550

Rev.2.1_01 www.DataSheet4U.com STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series The S-8550/8551 Series is a CMOS synchronous rectification step-down switching regulator which mainly consists of a reference voltage circuit, an oscillator, an error amplifier, a phase compensation circuit, a PWM controller, an under voltage lockout circuit (UVLO), a current limit circuit, and a power MOS FET. The oscillation frequency is high at 1.2 MHz, so a high efficiency, large output current, step-down switching regulator can be achieved by using small external parts. The built-in synchronous rectification circuit makes achieving high efficiency easier compared with conventional step-down switching regulators. A ceramic capacitor can be used as an output capacitor. High-density mounting is supported by adopting a small SOT-23-5 package. The S-8550 and S-8551 Series are offered according to different pin configuration. „ Features Oscillation frequency : 1.2 MHz Input voltage range : 2.0 to 5.5 V Output voltage range : Arbitrarily settable by external output voltage setting resistor Output current : 600 mA Reference voltage : 0.6 V ±2.0% Efficiency : 92% Soft-start function : 1 ms typ. Shutdown function : Shutdown current consumption : 1.0 µA max. Built-in current limit circuit Pch power MOS FET on-resistance : 0.4 Ω typ. Nch power MOS FET on-resistance : 0.3 Ω typ. Constant continuous mode operation (no light ...