1.5 A / 3.3 V step-down DC-DC converter
demonstration board based on the ST1S03A
Features
■ Step-down current mode PWM (1.5 MHz)
DC-DC converter
■ 2% DC output voltage tolerance
■ Internal soft-start for start-up current limitation
and power on delay of 50-100 µs
■ Typical efficiency: > 85%
■ Inhibit function
■ 1.5 A output current capability
■ Not switching quiescent current: max 1.5 mA
(overtemperature range)
■ Switch V
■ Uses tiny capacitors and inductors
■ RoHS compliant
: max 200 mV @ ISW = 750 mA
DS
STEVAL-ISA047V2
Data brief
STEVAL-ISA047V2
Description
This demonstration board is based on the
ST1S03A, an adjustable current mode PWM
step-down DC-DC converter with internal 1.5 A
power switch, packaged in a 6-lead DFN 3x3 mm.
It's a complete 1.5 A switching regulator with its
internal compensation eliminating additional
component.
The constant frequency, current mode, PWM
architecture and stable operation with ceramic
capacitors results in low, predictable output ripple.
However, in order to maximize the power
conversion efficiency with light load, the regulator
reduces automatically the switching frequency
when the output load becomes less than 250 mA
typically.
July 2009 Doc ID 15973 Rev 1 1/4
For further information contact your local STMicroelectronics sales office.
www.st.com
4
Circuit schematic STEVAL-ISA047V2
1 Circuit schematic
Figure 1. Schematic diagram
2/4 Doc ID 15973 Rev 1
STEVAL-ISA047V2 Revision history
2 Revision history
Table 1. Document revision history
Date Revision Changes
01-Jul-2009 1 Initial release.
Doc ID 15973 Rev 1 3/4
STEVAL-ISA047V2
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4/4 Doc ID 15973 Rev 1
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