Data Brief
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March 2008 Rev 1 1/4
4
STEVAL-ISA045V2
2 A / 3.3 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: 3.3 V
■Max Iout: 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-ISA045V2
www.st.com
Circuit schematic STEVAL-ISA045V2
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
6PG
C1
R3
GND
Vin
STEVAL-ISA045V2 Revision history
3/4
2 Revision history
Table 1. Document revision history
Date Revision Changes
03-Mar-2008 1 Initial release.
STEVAL-ISA045V2
4/4
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