UCC28C40, UCC28C41, UCC28C42, UCC28C43, UCC28C44, UCC28C45

UCC38C40, UCC38C41, UCC38C42, UCC38C43, UCC38C44, UCC38C45

SLUS458E -- AUGUST 2001 -- REVISED OCTOBER 2010

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLER

1

www.ti.com

FEATURES

D

Enhanced Replacement for UC3842A Family

With Pin-to-Pin Compatibility

D

1-MHz Operation

D

50-μA Standby Current, 100-μA Maximum

D

Low Operating Current of 2.3 mA at 52 kHz

D

Fast 35-ns Cycle-by-Cycle Overcurrent

Limiting

D

Rail-to-Rail Output Swings with 25-ns Rise

and 20-ns Fall Times

Reference

D

Trimmed Oscillator Discharge Current

D

New Under Voltage Lockout Versions

D

MSOP-8 Package Minimizes Board Space

APPLICATIONS

D

Switch-Mode Power Supplies

D

dc-to-dc Converters

D

Board Mount Power Modules

DESCRIPTION

UCC38C4x family is a high-performance current-

mode PWM controller. It is an enhanced BiCMOS

version with pin-for-pin compatibility to the

industry standard UC384xA family and UC384x

family of PWM controllers. In addition, lower

startup voltage versions of 7 V are offered as

UCC38C40 and UCC38C41.

Providing necessary features to control fixed

frequency, peak current-mode power supplies,

this family offers the following performance

advantages. The device offers high-frequency

operation up to 1 MHz with low start-up and

operating currents, thus minimizing start-up loss

and low operating power consumption for

improved efficiency. The device also features a

very fast current-sense-to-output delay time of

35 ns and a ±1 A peak output current capability

with improved rise and fall times for driving large

external MOSFETs directly.

The UCC38C4x family is offered in 8-pin

packages, MSOP (DGK), SOIC (D) and PDIP (P).

FUNCTIONAL BLOCK DIAGRAM

UDG--99139

8

2

4

7

VREF

Note: Toggle flip--flop used only in UCC38C41, UCC38C44, and UCC38C45.

VREF

RT/CT

VDD

5GND

6OUT

OSC

T

SQ

Q

R

FB

2R

R

1V

1

COMP

3

CS

UVLO

ERROR AMP

(NOTE)

+

+

5.0 V

2.5 V

VREF

GOOD LOGIC

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Copyright © 2003 -- 2010, Texas Instruments Incorporated

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments

semiconductor products and disclaimers thereto appears at the end of this data sheet.