STEP-DOWN, SYNCHRONOUS PWM CONTROL

SWITCHING REGULATOR CONTROLLER

S-8533 Series

Seiko Instruments Inc.

1

The S-8533 Series is a synchronous PWM control CMOS step-down

switching regulator controller that includes a reference voltage source,

synchronous

circuit,

oscillation

circuit,

error

amplifier,

phase

compensation circuit, and PWM controller.

An efficient step-down switching regulator can be realized simply by

adding external P-channel and N-channel power MOS FETs, one coil,

and three capacitors.

Since the oscillation frequency is a high 300 kHz, the S-8533 can be

used to configure a high efficiency step-down switching regulator

capable of driving high output current using small external parts and a

3 to 10% increase in efficiency is obtained compared to conventional

step-down switching regulators.

The 8-Pin TSSOP package and high oscillation frequency make the S-

8533 ideal as the main power supply for portable devices.

Features

• Synchronous rectification system realizing high efficiency (typ. 94%)

• Use at maximum duty ratio = 100% and use of a battery up to maximum life is possible by using P-channel and N-

channel power MOS FETs externally.

• Oscillation frequency :

300 kHz typ.

• Input voltage :

2.7 to 16.0 V

• Output voltage :

1.25 V

1.3 to 6.0 V, selectable in 0.1 V steps

• Output voltage accuracy : ±2.0%

• Soft-start function set by an external capacitor (C

• Shutdown function

• Small package :

8-Pin TSSOP

• Lead-free products

Applications

• Constant voltage power supply for hard disks and DVD drivers

• Power supplies for portable devices, such as digital cameras, PDAs, electronic organizers, and cellular phones

• Main or sub power supply for notebook PCs and peripherals

• Constant voltage power supply for cameras, video equipment, and communication equipment

Package

Drawing Code

Package Name

Package

Tape

Reel

8-Pin TSSOP

FT008-A

FT008-E

FT008-E