LM2854 Datasheet, PDF (1/22 Pages) National Semiconductor (TI) – 4A 500 kHz / 1 MHz PowerWise® Synchronous SIMPLE SWITCHER® Buck Regulator

April 2, 2008
LM2854
4A 500 kHz / 1 MHz PowerWise® Synchronous SIMPLE
SWITCHER® Buck Regulator
General Description
The LM2854 PowerWise^® SIMPLE SWITCHER^® buck regu-
lator is a 500 kHz or 1 MHz step-down switching voltage
regulator capable of driving up to a 4A load with exceptional
power conversion efficiency, line and load regulation, and
output accuracy. The LM2854 can accept an input voltage rail
between 2.95V and 5.5V and deliver an adjustable and highly
accurate output voltage as low as 0.8V. Externally estab-
lished soft-start with a small capacitor facilitates controlled
start-up, and the LM2854 is capable of starting gracefully into
a pre-biased output voltage. Partial internal compensation re-
duces the number of external passive components and PC
board space typically necessary in a voltage mode buck con-
verter application, yet preserving flexibility to deal with ce-
ramic and/or electrolytic based load capacitors. Lossless
cycle-by-cycle peak current limit is used to protect the load
from an overcurrent or short-circuit fault, and an enable com-
parator simplifies sequencing applications. The LM2854 is
available in an exposed pad TSSOP-16 package that en-
hances the thermal performance of the regulator.
Features
■ ^{Input voltage range of 2.95V to 5.5V}
■ ^{Maximum load current of 4A}
■ ^{Wide bandwidth voltage mode control loop, partial internal}
compensation
■ ^{Fixed switching frequency of 500 kHz or 1 MHz}
■ ^{35 mΩ integrated MOSFET switches}
■ ^{Adjustable output voltage down to 0.8V}
■ ^{Optimized reference voltage initial accuracy and}
temperature drift
■ ^{External soft-start control with tracking capability}
■ ^{Enable pin with hysteresis}
■ ^{Low standby current of 230 µA}
■ ^{Pre-biased load startup capability}
■ ^{Integrated UVLO, OCP and thermal shutdown}
■ ^{100% duty cycle capability}
■ ^{eTSSOP-16 exposed pad package}
Applications
■ ^{Low Voltage POL Regulation from 5V or 3.3V Rail}
■ ^{Local Solution for FPGA/DSP/ASIC/µP Core or I/O Power}
■ ^{Broadband Networking and Communications}
Infrastructure
■ ^{Portable Computing}
Typical Application Circuit
SIMPLE SWITCHER® is a Registered Trademark of National Semiconductor Corporation.
© 2008 National Semiconductor Corporation 300528
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