Rev.2.1
_01
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 load mode)
•
Small package :
SOT-23-5
•
Lead-free products
Applications
•
Mobile devices, such as mobile phones, Bluetooth devices, wireless devices, digital audio players, digital still
cameras, portable DVD players, and portable CD players
Package
Package Name
SOT-23-5
Drawing Code
Package
MP005-A
Tape
MP005-A
Reel
MP005-A
Seiko Instruments Inc.
1
SII [ SEIKO INSTRUMENTS INC ]
