SWITCHING REGULATORS. S-8550 Datasheet
STEP-DOWN, BUILT-IN FET, SYNCHRONOUS
RECTIFICATION, PWM CONTROL SWITCHING REGULATORS
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
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.
• Oscillation frequency :
• Input voltage range :
2.0 to 5.5 V
• Output voltage range :
Arbitrarily settable by external output voltage setting resistor
• Output current :
• Reference voltage :
0.6 V ±2.0%
• Efficiency :
• 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)
• Small package :
• Lead-free products
• Mobile devices, such as mobile phones, Bluetooth devices, wireless devices, digital audio players, digital still
cameras, portable DVD players, and portable CD players
Seiko Instruments Inc.
www.DaStaTSEhPe-eDt4OUW.coNm, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS
+ PWM control
*1. Parasitic diode
2 Seiko Instruments Inc.