Power Management ICs

Step-Down, Built-in FET, Synchronous Rectification, PWM Control Switching Regulator (DC-DC Converter ICs) S-8550 Series

The S-8550 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 packages small SOT-23-5 and super-small and thin SNT-8A.


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%
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 load mode)
Lead-free, Sn 100%, halogen-free


  • Mobile devices, such as mobile phones, Bluetooth devices, wireless devices, digital audio players, digital still cameras, portable DVD players, and portable CD players

Standard Circuit

Standard Circuit