UCC28C40, UCC28C41, UCC28C42, UCC28C43, UCC28C44, UCC28C45
UCC38C40, UCC38C41, UCC38C42, UCC38C43, UCC38C44, UCC38C45
SLUS458B – AUGUST 2001
BiCMOS LOW POWER CURRENT MODE PWM CONTROLLER
FEATURES
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
50 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).
D
D
D
D
D
D
D
D
D
1-MHz Operation
50-µA Start-Up Current, 100-µA Maximum
Low Operating Current of 2.3 mA at 52 kHz
50-ns Cycle-by-Cycle Overcurrent Limiting
±1-A
Peak Output Current
Rail-to-Rail Output Swings with 25-ns Rise
and 20-ns Fall Times
±1%
Initial Trimmed 2.5-V Error Amplifier
Reference
Trimmed Oscillator Discharge Current
MSOP-8 Package Minimizes Board Space
APPLICATIONS
D
Switch-Mode Power Supplies
D
dc-to-dc Converters
D
Board Mount Power Modules
FUNCTIONAL BLOCK DIAGRAM
VREF 8
5.0 V
VREF
UVLO
VREF
GOOD LOGIC
7
+
+
5
VDD
GND
RT/CT 4
2.5 V
FB
2
OSC
(NOTE)
+
ERROR AMP
2R
R
1V
T
S Q
R Q
6
OUT
COMP 1
CS
3
Note: Toggle flip–flop used only in UCC38C41, UCC38C44, and UCC38C45.
UDG–99139
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.
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
2001, Texas Instruments Incorporated
www.ti.com
1
ETC [ ETC ]
