WIDE INPUT 2A STEP DOWN CONVERTER

2007-5-28

1/9

FSP3126

PIN ASSIGNMENT

(Top View)

PIN DESCRIPTION

Name

No.

Description

BS

1

Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver.

Connect a 10nF capacitor between BS and SW.

IN

2

Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor

in the Application Information section.

SW

3

Switch Output. Connect this pin to the switching end of the inductor.

G

4

Ground.

FB

5

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.

COMP

6

Compensation Pin. See Stability Compensation in the Application Information

section.

EN

7

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.

N/C

8

Not Connected.

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

BS

IN

SW

G

N/C

EN

COMP

FB

FSP3126

8

7

6

5

1

2

3

4

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.

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