UNISONIC TECHNOLOGIES CO., LTD

UC3551

Preliminary

CMOS IC

www.unisonic.com.tw

1 of 6

Copyright © 2011 Unisonic Technologies Co., Ltd

QW-R502-555.a

ADVANCED PWM STEP-UP

DC-DC CONVERTER

DESCRIPTION

The UTC UC3551 is a step-up DC/DC converter with high

efficiency and low start-up voltage. It is operaded in stable

waveforms without external compensate. This device incorporates

an adaptive current mode PWM control loop in which an error

amplifier, ramp generator, comparator, switch pass element and

driver are included. Besides, this circuit provides a stable and high

efficient operation over a wide range of load currents.

The UTC UC3551 features high switching rate which is up to 450

KHz, making the external component counts less required.

Moreover, it features 17μA low quiescent current, which makes the

battery life longer. The low start-up input voltage below 1V makes

UTC UC3551 suitable for 1 to 4 battery cells applications of

providing up to 300mA output current.

Two external resistors determine the value of the output voltage.

The external power devices (NMOS or NPN) are derived by both

internal 2A switch and driver.

The UTC UC3551 is intended to be used in PDA, DSC, LCD

Panel, RF-Tags, MP3, portable instrument and wireless equipment.

FEATURES

* Low Start-up Input Voltage is as Low as 1.0V

* Efficiency up to 90%

* High Supply Capability to Deliver 3.3V 100mA with 1 Alkaline Cell

* Quiescent (Switch-off) Supply Current: 17µA

* Zero Shutdown Mode Supply Current

* Fixed Switching Frequency: 450KHz

* Both Internal and External Power Switches for Maximum Flexibility

ORDERING INFORMATION

Ordering Number

Lead Free

Halogen Free

Package

Packing

UC3551L-AG6-R

UC3551G-AG6-R

SOT-26

Tape Reel

UC3551L-AG6-R

(1)Packing Type

(2)Package Type

(1) R: Tape Reel

(2) AG6: SOT-26

(3) G: Halogen Free, L: Lead Free

(3)Lead Free