Cs51033 (Ic 104); General Description; Features; Pin Description - Sharp 32LF-94EC Service Manual

12.4.CS51033 (IC 104)

12.4.1.General Description

The CS51033 is a switching controller for use in dc–dc converters. It can be used in the buck topology
with a minimum number of external components. The CS51033 consists of a 1.0 A power driver for
controlling the gate of a discrete P–channel transistor, fixed frequency oscillator, short circuit protection
timer, programmable Soft Start, precision reference, fast output voltage monitoring 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 u p. The
short circuit protection timer significantly reduces the PFET duty cycle to approximately 1/30 of its
normal cycle during short circuit conditions.
The CS51033 is available in an 8–Lead SO package.

12.4.2.Features

• 1.0 A Totem Pole Output Driver
• High Speed Oscillator (700 kHz max)
• No Stability Compensation Required
• Lossless Short Circuit Protection
• 2.0% Precision Reference
• Programmable Soft Start
• Wide Ambient Temperature Range:
Industrial Grade: –40°C to 85°C
Commercial Grade: 0°C to 70°C

12.4.3.Pin Description

PIN NUMBER PIN SYMBOL
1 V
2 P
3 C
4 GND
5 V
6 V
7 CS
8 V
AK53 D.O.C. Service Manual
FUNCTION
Driver pin to gate of external PFET.
GATE
Output power stage ground connection.
GND
Oscillator frequency programming capacitor.
OSC
Logic ground.
Feedback voltage input.
FB
Logic supply voltage.
CC
Soft Start and fault timing capacitor.
Driver supply voltage.
C
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22/03/2004