FSP3131 Datasheet, PDF (1/7 Pages) FOSLINK SEMICONDUCTOR CO.,LTD – PWM CONTROL 3A STEP-DOWN CONVERTER

„ FEATURES
z Input voltage: 3.6V to 23V.
z Output voltage: 0.8V to VCC.
z Duty ratio: 0% to 100% PWM control
z Oscillation frequency: 300KHz typ.
z Soft-start, Current limit, Enable function
z Thermal Shutdown function
z Built-in internal SW P-channel MOSFET
z SOP8L Package.
„ TYPICAL APPLICATION
z Cellular Phones
z PC Motherboard
z LCD Monitor
z Graphic Card
z DVD-Video Player
z Telecom Equipment
z ADSL Modem
z Printer and other Peripheral Equipment
z Microprocessor core supply
z Networking power supply
„ PIN ASSIGNMENT
(Top View)
FB 1
EN 2
OCSET 3
VCC 4
8 VSS
7 VSS
6 OUTPUT
5 OUTPUT
PWM CONTROL 3A STEP-DOWN CONVERTER
FSP3131
„ GENERAL DESCRIPTION
FSP3131 consists of step-down switching regulator
with PWM control. These devices include a
reference voltage source, oscillation circuit, error
amplifier and internal PMOS.
FSP3131 provides low-ripple power, high efficiency,
and excellent transient characteristics. The PWM
control circuit is able to vary the duty ratio linearly
from 0 up to 100%. This converter also contains an
error amplifier circuit as well as a soft-start circuir
that prevents overshoot at startup. An enable
function, an over current protect function and a
short circuit protect function are built inside, and
when OCP or SCP happens, the operation
frequency will be reduced from 300KHz to 30KHz.
Also, an internal compensation block is built in to
minimum external component count.
With the addition of an internal P-channel Power
MOS, a coil, capacitors, and a diode connected
externally, these ICs can function as step-down
switching regulators. They serve as ideal power
supply units for portable devices when coupled with
the SOP8L mini-package, providing such
outstanding features as low current consumption.
Since this converter can accommodate an input
voltage up to 23V, it is also suitable for the operation
via an AC adapter.
„ PIN DESCRIPTION
Pin Number Pin Name
Pin Description
1
FB Feedback Pin
Enable Input Pin
2
EN H: Normal operation(Step-down operation)
L: Step-down operation stopped(All circuits deactivated)
3
OCSET Add an external resistor to set max output current
4
VCC IC power supply pin
5,6
OUTPUT
Switch pin. Connect external inductor/diode here. Minimize trace area at this pin to
reduce EMI.
7,8
VSS GND pin
1/7
2007-6-6