LM2717 Datasheet, PDF (1/12 Pages) National Semiconductor (TI) – Dual Step-down DC/DC Converter

PRELIMINARY
May 2005
LM2717
Dual Step-down DC/DC Converter
General Description
The LM2717 is composed of two PWM DC/DC buck (step-
down) converters. The first converter is used to generate a
fixed output voltage of 3.3V. The second converter is used to
generate an adjustable output voltage. Both converters fea-
ture low R_DSON (0.16Ω) internal switches for maximum effi-
ciency. Operating frequency can be adjusted anywhere be-
tween 300kHz and 600kHz allowing the use of small external
components. External soft-start pins for each enables the
user to tailor the soft-start times to a specific application.
Each converter may also be shut down independently with
its own shutdown pin. The LM2717 is available in a low
profile 24-lead TSSOP package ensuring a low profile over-
all solution.
Features
n Fixed 3.3V output buck converter with a 2.2A, 0.16Ω,
internal switch
n Adjustable buck converter with a 3.2A, 0.16Ω, internal
switch
n Operating input voltage range of 4V to 20V
n Input undervoltage protection
n 300kHz to 600kHz pin adjustable operating frequency
n Over temperature protection
n Small 24-Lead TSSOP package
Applications
n TFT-LCD Displays
n Handheld Devices
n Portable Applications
n Laptop Computers
Typical Application Circuit
© 2005 National Semiconductor Corporation DS200785
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