CS51031
Fast PFET Buck Controller
Features
Description
The CS51031 is a switching con-
troller for use in DC-DC converters. allows the use of small inductors
The high frequency oscillator
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1A Totem Pole Output Driver
High Speed Oscillator (700kHz
max)
It can be used in the buck topology
with a minimum number of exter-
nal components. The CS51031 con-
sists of a VCC 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.
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.
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No Stability Compensation
Required
Lossless Short Circuit
Protection
ꢀ
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VCC Monitor
2% Precision Reference
Programmable Soft Start
The CS51031 is available in 8 Lead
SO and 8 Lead PDIP plastic pack-
ages.
Wide Ambient Temperature
Range:
Industrial Grade: –40°C to 85°C
Commercial Grade: 0°C to 70°C
Typical Application Diagram
5V - 12V
C
IN
Package Options
47µF
20Ω
8 Lead SO Narrow & PDIP
MP
IRF7416
1
VGATE
1
VC
V
GATE
V
PGnd
COSC
CS
V
C
GATE
MBRS360
VCC
CS
PGnd
D
1
VFB
Gnd
CS
0.1µF
L
RV
10Ω
CC
CS51031
4.7µH
V
C
OSC
CC
CV
CC
C
150pF
OSC
100µF
100
.01µF
R
B
V
V
O
FB
Gnd
3.3V @ 3A
2.5kΩ
C
0.1µF
RR
R
1.5kΩ
A
C
O
100µF × 2
ON Semiconductor
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885–3600 Fax: (401)885–5786
N. American Technical Support: 800-282-9855
Web Site: www.cherry–semi.com
May, 2000 - Rev. 4
1