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February 2013 Doc ID 024148 Rev 1 1/4
4
STEVAL-ISA108V1
4 A, 850 kHz fixed-frequency PWM synchronous step-down
demostration board based on the ST1S41 in a VFQFPN package
Data brief
Features
■4 to 18 V input voltage
■Output voltage adjustable from 0.8 V
■850 kHz switching frequency
■Internal soft-start
■Integrated 95 mΩ and 69 mΩ power MOSFETs
■All ceramic capacitor
■Enable function
■Cycle-by-cycle current limiting
■Current fold-back short-circuit protection
■RoHS compliant
Description
Based on the ST1S41 step-down switching
regulator, the STEVAL-ISA108V1 demonstration
board is an internally-compensated 850 kHz
fixed-frequency PWM synchronous step-down
converter.
The ST1S41 operates from 4.0 V to 18 V input,
while it regulates an output voltage as low as 0.8
V and up to VIN (100% duty cycle).
The ST1S41 integrates a 95 mΩ high side switch
and 69 mΩ low side synchronous rectifier,
resulting in very high efficiency with very low
output voltages.
The peak current mode control with internal
compensation offers a compact solution with a
minimum component count.
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Schematic diagram STEVAL-ISA108V1
2/4 Doc ID 024148 Rev 1
1 Schematic diagram
Figure 1. STEVAL-ISA108V1 circuit schematic
STEVAL-ISA108V1 Revision history
Doc ID 024148 Rev 1 3/4
2 Revision history
Table 1. Document revision history
Date Revision Changes
12-Feb-2013 1Initial release.
STEVAL-ISA108V1
4/4 Doc ID 024148 Rev 1
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