Data brief
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December 2011 Doc ID 022618 Rev 1 1/4
4
STEVAL-ISA093V1
3 A step-down switching power supply demonstration board
based on the L7981 (QFN)
Features
■3 A DC output current
■4.5 V to 28 V input voltage
■Output voltage adjustable from 0.6 V
■250 kHz switching frequency, programmable
up to 1 MHz
■Internal soft-start and enable
■Low dropout operation: 100% duty cycle
■Voltage feed-forward
■Zero load current operation
■Overcurrent and thermal protection
■RoHS compliant
Description
The STEVAL-ISA093V1 is a step-down switching
power supply based on STMicroelectronics’
L7981 switching regulator in a QFN package.
The L7981 features an embedded power
MOSFET and is capable of delivering up to 3 A of
current to the load, depending on the application
conditions.
The input voltage can range from 4.5 V to 28 V,
while the output voltage can be set from 0.6 V to
VIN.
Requiring a minimum number of external
components, the device includes an internal 250
kHz switching frequency oscillator that can be
externally adjusted up to 1 MHz.
STEVAL-ISA093V1
www.st.com
Schematic diagram STEVAL-ISA093V1
2/4 Doc ID 022618 Rev 1
1 Schematic diagram
Figure 1. STEVAL-ISA093V1 circuit schematic
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STEVAL-ISA093V1 Revision history
Doc ID 022618 Rev 1 3/4
2 Revision history
Table 1. Document revision history
Date Revision Changes
23-Dec-2011 1 Initial release.
STEVAL-ISA093V1
4/4 Doc ID 022618 Rev 1
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