UNISONIC TECHNOLOGIES CO., LTD

UC3550

CMOS IC

www.unisonic.com.tw

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Copyright © 2010 Unisonic Technologies Co., Ltd

QW-R502-082,B

PWM CONTROLLED， PWM/PFM

SWITCHABLE STEP-UP DC-DC

CONTROLLER

DESCRIPTION

The UTC UC3550 series is a compact, high efficiency, step-up

DC/DC controllers includes an error amplifier, oscillator, PWM

comparator, skip cycle comparator, voltage reference, soft-start, and

high speed lower ON-resistance driver for driving external power

devices (NMOS or NPN) ,Additionally, a CE (chip enable) function that

reduces power consumption during shut-down mode.

That typically operated from a single-or dual-cell battery packs. It

have a driver pin ,ext pin, for connecting to an external transistor(NMOS

or NPN). a lower ON-resistance external transistor can obtain larger

output current. With only external components, this series allow a

simple means to accommodate high output current applications.

The UTC UC3550 series goes automatically into skip switching

cycles under light load condition to maintain high efficiency.

FEATURES

* Input Voltage Range：0.9~8V

* Output Voltage Range：1.8~6V Programmable in 0.1V with High

Accuracy ± 2.5%

* High Efficiency 88% (Typ.)

* Oscillator Frequency: 300kHz.(±20%)

* Chip Enable Pin with Pull-up Current Source

SOT-25

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ORDERING INFORMATION

Order Number

Package

Packing

UC3550G-xx-AF5-R

SOT-25

Tape Reel