WIDE INPUT 2A STEP DOWN CONVERTER
FSP3126
FEATURES
2A Output Current
Up to 95% Efficiency
4.75V to 20V Input Range
8µA Shutdown Supply Current
410kHz Switching Frequency
Adjustable Output Voltage
Cycle-by-Cycle Current Limit Protection
Thermal Shutdown Protection
Frequency Foldback at Short Circuit
Stability with Wide Range of Capacitors,
Including Low ESR Ceramic Capacitors
SOP8L Package
GENERAL DESCRIPTION
The FSP3126 is a current-mode step-down DC/DC
converter that generates up to 2A of output current at
410kHz switching frequency. The device utilizes
ISOBCD20 process for operation with input voltages
up to 20V.
Consuming only 8µA in shutdown mode, the
FSP3126 is highly efficient with peak operating
efficiency at 95%. Protection features include
cycle-by-cycle current limit, thermal shutdown, and
frequency foldback at short circuit.
The FSP3126 is available in a SOP8L package and
requires very few external devices for operation.
Typical Application
TFT LCD Monitors
Portable DVDs
Car-Powered or Battery-Powered Equipments
Set-Top Boxes
Telecom Power Supplies
DSL and Cable Modems and Routers
Termination Supplies
PIN ASSIGNMENT
(Top View)
BS 1
IN
SW
G
2
3
4
8
7
N/C
EN
COMP
FB
FSP3126
6
5
PIN DESCRIPTION
Name
BS
IN
SW
G
FB
COMP
EN
N/C
No.
1
2
3
4
5
6
7
8
Description
Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver.
Connect a 10nF capacitor between BS and SW.
Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor
in the 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 1.293V. Connect to the
resistor divider between output and ground to set output voltage.
Compensation Pin. See Stability Compensation in the Application Information
section.
Enable Input. When higher than 1.3V, this pin turns the IC on. When lower than
0.7V, this pin turns the IC off. Output voltage is discharged when the IC is off.
When left unconnected, EN is pulled up to 4.5V tip with a 2µA pull up current.
Not Connected.
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2007-5-28
FOSLINK [ FOSLINK SEMICONDUCTOR CO.,LTD ]
