WIDE INPUT 2A STEP-DOWN CONVERTER
FSP3129
FEATURES
2A Output Current
Up to 95% Efficiency
Up to 30V Input Range
6µA Shutdown Supply Current
400kHz Switching Frequency
Adjustable Output Voltage
Cycle-by-Cycle Current Limit Protection
Thermal Shutdown Protection
Frequency Fold Back at Short Circuit
Stability with Wide Range of Capacitors,
Including Low ESR Ceramic Capacitors
SOP8L Package
GENERAL DESCRIPTION
The FSP3129 is a current-mode step-down DC/DC
converter that generates up to 2A output current at
400kHz switching frequency. The device can
operate with input voltage up to 30V.
Consuming only 6µA in shutdown mode, the
FSP3129 is highly efficient with peak efficiency at
95% when in operation. Protection features include
cycle-by-cycle current limit, thermal shutdown, and
frequency fold back at short circuit.
The FSP3129 is available in SOP8L package and
requires very few external devices for operation.
TYPICAL APPLICATION
TFT
LCD Monitors or Televisions and HDTV
Portable DVD Players
Car-Powered or Battery-Powered Equipment
Set-Top Boxes
Telecom Power Supplies
DSL and Cable Modems and Routers
PIN ASSIGNMENT
(Top View)
BS 1
IN
2
8
7
6
5
N/C
EN
COMP
FB
SW 3
G
4
PIN DESCRIPTION
Pin Number Pin Name
1
2
3
4
5
6
7
8
BS
IN
SW
G
FB
COMP
EN
N/C
Pin Description
Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver.
Connect a 10nF between this pin and SW.
Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor in
Application Information section.
Switch Output. Connect this pin to the switching end of the inductor.
Ground.
Feedback Input. The voltage at this pin is regulated to 1.222V. Connect to the resistor
divider between the output and ground to set output voltage.
Compensation Pin. See Compensation Technique in Application information section.
Enable Input. Drive higher than 1.3V or unconnected to enable the IC. Drive lower than
0.7V to disable the IC. The IC is in 6µA low current shutdown mode and the output is
discharged through the Low-Side Power Switch. This pin has a small internal pull up
current to a high level voltage when pin is not connected.
Not Connected.
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2007-1-4
FOSLINK [ FOSLINK SEMICONDUCTOR CO.,LTD ]
