CS51031
CS51031
Fast PFET Buck Controller
Does Not Require Compensation
Description
The CS51031 is a switching con-
troller for use in DC-DC converters.
It can be used in the buck topology
with a minimum number of exter-
nal components. The CS51031 con-
sists of a V
CC
monitor for control-
ling the state of the device, 1.0A
power driver for controlling the
gate of a discrete P-channel transis-
tor, fixed frequency oscillator, short
circuit protection timer, pro-
grammable soft start, precision ref-
erence, fast output voltage monitor-
ing comparator, and output stage
driver logic with latch.
The high frequency oscillator
allows the use of small inductors
and output capacitors, minimizing
PC board area and systems cost.
The programmable soft start
reduces current surges at start up.
The short circuit protection timer
significantly reduces the duty cycle
to approximately 1/30 of its cycle
during short circuit conditions.
The CS51031 is available in 8L SO
and 8L PDIP plastic packages.
Features
s
1A Totem Pole Output
Driver
s
High Speed Oscillator
(700kHz max)
s
No Stability
Compensation Required
s
Lossless Short Circuit
Protection
s
V
CC
Monitor
s
2% Precision Reference
s
Programmable Soft Start
Typical Application Diagram
5V - 12V
C
IN
47mF
20W
MP
1
IRF7416
Package Options
8 Lead SO Narrow & PDIP
V
GATE
1
V
GATE
V
GATE
PGnd
V
C
CS
V
CC
V
FB
V
C
MBRS360
CS
RV
CC
10W
CV
CC
100mF
CS
0.1mF
D
1
L
4.7mH
PGnd
C
OSC
Gnd
CS51031
C
OSC
C
OSC
150pF
Gnd
V
CC
V
FB
100
.01mF
R
B
2.5kW
V
O
3.3V @ 3A
R
A
1.5kW
C
RR
0.1mF
C
O
100mF
´
2
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
Rev. 2/13/98
1
A
¨
Company
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
