S-8533 Series

www.sii-ic.com

STEP-DOWN, SYNCHRONOUS PWM CONTROL

SWITCHING REGULATOR CONTROLLER

© SII Semiconductor Corporation, 2002-2010

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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.

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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%

• Shutdown function

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

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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

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Package

• 8-Pin TSSOP