S-8550 Series

www.sii-ic.com

STEP-DOWN, BUILT-IN FET, SYNCHRONOUS

RECTIFICATION, PWM CONTROL SWITCHING REGULATORS

© SII Semiconductor Corporation, 2007-2015

1

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.



Features

• Oscillation frequency:

1.2 MHz

• Input voltage range:

2.0 V 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 load mode)

*1. Refer to “ Product Name Structure” for details.



Applications

• Mobile devices, such as mobile phones, Bluetooth devices, wireless devices, digital audio players, digital still

cameras, portable DVD players, and portable CD players



Packages

• SOT-23-5

• SNT-8A