For further information contact your local STMicroelectronics sales office.
May 2013 DocID024676 Rev 1 1/4
4
STEVAL-ISA042V1
1.5 A / 1.2 V step-down DC-DC converter demonstration board
based on the ST1S03
Data brief
Features
•Adjustable current-mode PWM step-down DC-
DC converter
•Output voltage, Vout: 1.2 V
•Output current, Iout: 1.5 A
•Internal compensation to eliminate additional
components
•Pulse skipping for Iout lower than 15 mA, to
maintain the regulation with light loads
•RoHS compliant
Description
The STEVAL-ISA042V1 demonstration board is a
step-down DC-DC converter based on ST’s
ST1S03 switching regulator, 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. It is thermally protected and
current limited to prevent damage due to
accidental short-circuits.
The ST1S03 is available in a DFN6 (3x3 mm)
package.
STEVAL-ISA042V1
www.st.com
Circuit schematic STEVAL-ISA042V1
2/4 DocID024676 Rev 1
1 Circuit schematic
Figure 1. STEVAL-ISA042V1 demonstration board schematic
$09
DocID024676 Rev 1 3/4
STEVAL-ISA042V1 Revision history
2 Revision history
Table 1. Document revision history
Date Revision Changes
21-May-2013 1 Initial release.
STEVAL-ISA042V1
4/4 DocID024676 Rev 1
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