S1F71100 Series

S1F71100 Series PWM Type Step-down DC/DC Switching Regulator

DESCRIPTION

S1F71100 is a pulse width modulation (PWM) type step-down DC/DC converter control IC for which the CMOS process is used and to which a power transistor is connected outside. S1F71100 is composed of an os- cillator, a reference voltage circuit, an error amplifier, a PWM circuit, a soft start circuit, a driver, etc. When this IC drives an external P ch power MOS transistor, S1F71100 can constitute a step-down DC/DC converter that converts input voltages up to 12V into the output voltage of 3.3V.

S1F71100 is also provided with a low-voltage protection circuit, an overcurrent protection circuit and a soft start protection circuit. When receiving external sig- nals, S1F71100 can stop the oscillator and the switching circuit and turn off the power, so that it can reduce wasteful current consumption at the time of system halt.

FEATURES

•Input voltage : 3.3V ~ 12V

•Output voltage : 3.3V (S1F71100M0A0)

•Power off current : 1μA

•Self current consumption : 800μA

•Frequency fixing (200kHz) PWM

•Power off function (IC shutdown)

•Soft start function

•Overcurrent protection function

•Low-voltage protection function

•Shipping pattern : plastic package SOP4-8pin

*Radiation-resistant design has not been provided for this specification.

BLOCK DIAGRAM

 

VDD

 

Low-voltage

 

protection circuit

POFFX

+

 

–

 

Reference

 

voltage circuit

SSCAP

Soft start

Oscillator

VO

+

PWM circuit

ERCAP –

Error amplifier

VSS

Overcurrent protection circuit

–

+

ISENSE

Driver

SWO

4–34

EPSON

S1F70000 Series Technical Manual