Liteon Semiconductor Corporation
LSP3125A
150KHZ 2A PWM Buck DC/DC Converter
Rev1.4
1/9
GENERAL DESCRIPTION
T
he LSP3125A series are monolithic IC designed for
a step-down DC/DC converter, and own the ability of
driving a 2A load without additional transistor. It saves
board space. The external shutdown function can be
controlled by logic level and then come into standby
mode. The internal compensation makes feedback
control having good line and load regulation without
external design. Regarding protected function,
thermal shutdown is to prevent over temperature
operating from damage, and current limit is against
over current operating of the output switch. If current
limit function occurs and FB is down below 0.5V, the
switching frequency will be reduced. The LSP3125A
series operates at a switching frequency of 150KHz
thus allow smaller sized filter components than what
would be needed with lower frequency switching
regulators. Other features include a guaranteed ± 4%
tolerance on output voltage under specified input
voltage and output load conditions, and ± 15% on the
oscillator frequency. The output version included fixed
3.3V, 5V, 12V, and an adjustable type. The chips are
available in a standard SOP8L package.
FEATURES
Output voltage: 3.3V, 5V, 12V and adjustable
output version
Adjustable version output voltage range, 1.23V
to 37V ± 4%
150KHz ±15% fixed switching frequency
Voltage mode non-synchronous PWM control
Thermal-shutdown and current-limit protection
ON/OFF shutdown control input
Operating voltage can be up to 40V
Output load current: 2A
SOP8L packages
Low power standby mode
Built-in switching transistor on chip
TYPICAL APPLICATION
Simple High-efficiency step-down regulator
On-card switching regulators
Positive to negative converter
PIN ASSIGNMENT
(Top View)
PIN DESCRIPTION
Name
No.
Description
VIN
1
Operating Voltage Input
OUTPUT
2
Switching Output
FB
3
Output Voltage Feedback Control
SD
4
On/Off Shutdown
GND
5
Ground
GND
6
Ground
GND
7
Ground
GND
8
Ground