STEVAL-ISA055V1 Datasheet, PDF (1/4 Pages) STMicroelectronics – Synchronous rectification

STEVAL-ISA055V1
0.7 A / 1.2 V synchronous buck converter
with enable function based on the ST1S12XX
Data Brief
Features
■ Step-down current mode PWM (1.7 MHz) DC-
DC converter
■ Fixed output voltage of 1.2 V
■ 0.7 A output current capability
■ 3% DC output voltage tolerance
■ Synchronous rectification
■ Enable function
■ Internal soft-start
■ Typical efficiency: > 90%
■ Not switching quiescent current: max 600 µA
over temperature range
■ R_DS(on) typ. 250 mΩ and 400 mΩ
■ Uses tiny capacitors and inductors
STEVAL-ISA055V1
Description
This demonstration board is based on the
ST1S12 family of synchronous step-down DC-DC
converters optimized for powering low-voltage
digital cores in HDD (hard disk drive) applications
and is generally used to replace high-current
linear solutions when power dissipation may
cause high heating of the application
environment.
It provides up to 0.7 A over an input voltage range
of 2.5 V to 5.5 V. A high switching frequency of 1.7
MHz allows the use of tiny surface-mount
components. For the adjustable version, a resistor
divider to set the output voltage value, an
inductor, and two capacitors are required. Only an
inductor and 2 capacitors are needed for the 1.2 V
and 1.8 V fixed version. A low output ripple is
guaranteed by the current mode PWM topology
and by the use of low ESR surface-mount ceramic
capacitors.
The ST1S12 device is thermal protected and
current limited to prevent damage due to
accidental short-circuit. This family of products is
available in the TSOT23-5L package.
September 2008
Rev 1
For further information contact your local STMicroelectronics sales office.
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