ST ISA042V2 User Manual

1.5 A / 3.3 V step-down DC-DC converter demonstration board

Features

■ Adjustable current-mode PWM step-down DC-

DC converter

■ Output voltage, V

■ Output current, I

■ Internal compensation to eliminate additional

components

■ Pulse skipping for I

maintain the regulation with light loads

■ RoHS compliant

: 3.3 V

out

: 1.5 A

out

lower than 15 mA, to

out

STEVAL-ISA042V2

based on the ST1S03

Data brief

Description

The STEVAL-ISA042V2 demonstration board is a
step-down DC-DC converter optimized for
powering the low-voltage digital core in HDD
applications and, more generally, replacing the
high-current linear solution when the power
dissipation may cause excessive heating of the
application environment. It provides up to 1.5 A
over an input voltage range of 3 V to 16 V.

A high switching frequency (1.5 MHz) allows the
use of tiny surface-mounted components, as well
as the use of a resistor divider to set the output
voltage value. Only an inductor, a Schottky diode,
and two capacitors are required. In addition, a low
output ripple is guaranteed by the current-mode
PWM topology and by the use of low ESR SMD
ceramic capacitors. The device is thermal
protected and current limited to prevent damage
due to accidental short-circuits.

It uses the ST1S03 device.

The ST1S03 is available in a DFN6 (3x3mm)
package.

STEVAL-ISA042V2

September 2010 Doc ID 18024 Rev 1 1/4

For further information contact your local STMicroelectronics sales office.

www.st.com

4

Circuit schematic STEVAL-ISA042V1

1 Circuit schematic

Figure 1. STEVAL-ISA042V2 demonstration board schematic

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2/4 Doc ID 18024 Rev 1