UD05201

Advance

CMOS IC

UNISONIC TECHNOLOGIES CO., LTD

5 of 5

www.unisonic.com.tw

QW-R115-003.c

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FUNCTION DESCRIPTIONS

Operation

UTC UD05201A/B/C is a monolithic switching mode Step-Down DC-DC converter. It utilizes internal MOSFETs to

achieve high efficiency and can generate very low output voltage by using internal reference at 0.6V. It operates at a

fixed switching frequency, and uses the slope compensated current mode architecture. This Step-Down DC-DC

Converter supplies 2000mA output current at input voltage range from 2.6V to 5.5V.

Current Mode PWM Control

Slope compensated current mode PWM control provides stable switching and cycle-by-cycle current limit for

excellent load and line responses and protection of the internal main switch (P-CH MOSFET) and synchronous

rectifier (N-CH MOSFET). During normal operation, the internal P-CH MOSFET is turned on for a certain time to

ramp the inductor current at each rising edge of the internal oscillator, and switched off when the peak inductor

current is above the error voltage. The current comparator, ICOMP limits the peak inductor current. When the main

switch is off, the synchronous rectifier will be turned on immediately and stay on until either the inductor current

starts to reverse, as indicated by the current reversal comparator, IZERO, or the beginning of the next clock cycle.

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TYPICAL APPLICATION CIRCUIT

UTC

UD05201

U1

PVIN

SVIN

EN

PGND

SGND

FB

LX

VIN=2.6~5.5V

R1

10R

L1

3.3uH

VOUT=1.8V

C2

22uF

C5

15pF

R2

600K

R3

300K

C3

100nF

C1

22uF

VOUT=0.6 × (1+R2/R3)

R2=510K~820K

UTC assumes no responsibility for equipment failures that result from using products at values that

exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other

parameters) listed in products specifications of any and all UTC products described or contained herein .

UTC products are not designed for use in life support appliances, devices or systems where malfunction

of these products can be reasonably expected to result in personal injury. Reproduction in whole or in

part is prohibited without the prior written consent of the copyright owner. UTC reserves the right to

make changes to information published in this document, including without limitation specifications and

product descriptions, at any time and without notice. This document supersedes and replaces all

information supplied prior to the publication hereof.