ST ISA045V1 User Manual

Data Brief

For further information contact your local STMicroelectronics sales office.

March 2008 Rev 1 1/4

4

STEVAL-ISA045V1

2 A / 1.2 V high-efficiency synchronous buck converter

evaluation board based on the ST1S09

Features

■ Input voltage range: 2.7 V to 5.5 V

■ Output voltage: 1.2 V

■ Max I

out

: 2 A

■ High internal switching frequency: 1.5 MHz

■ Short-circuit protection

■ ST1S09 in the DFN6 3x3 package

Description

This evaluation board, based on the ST1S09

family of synchronous step-down DC-DC

converters, is optimized for powering all low-

voltage applications and, generally, replaces high

current linear solutions when power dissipation

may cause high heating of the application

environment.

It provides up to 2 A over an input voltage range

of 2.7 V to 5.5 V.

A high 1.5 MHz switching frequency allows the

use of tiny surface-mount components and in

addition to the resistor divider to set the output

voltage value, an inductor and two capacitors are

required.

A low output ripple is guaranteed by the current

mode PWM topology and by the use of low ESR

surface-mount ceramic capacitors.

The device is thermally protected and current

limited to prevent damage due to accidental short-

circuit.

The ST1S09 family is available in the DFN6 3x3

package.

STEVAL-ISA045V1

www.st.com

Circuit schematic STEVAL-ISA045V1

2/4

1 Circuit schematic

Figure 1. Schematic

VF

VF

B

SW

GND

VIN_ A

VIN_ SW

ST1S09

2 1

5

4

3

R1

R2

L1

Vou

ou

t

C2

6

PG

C1

R3

GND

Vin