LM3100 Datasheet, PDF (1/15 Pages) National Semiconductor (TI) – SIMPLE SWITCHER® Synchronous 1MHz 1.5A Step-Down Voltage Regulator

February 2006
LM3100
SIMPLE SWITCHER^® Synchronous 1MHz 1.5A
Step-Down Voltage Regulator
General Description
The LM3100 Synchronously Rectified Buck Converter fea-
tures all functions needed to implement a highly efficient,
cost effective buck regulator capable of supplying 1.5A to
loads with voltages as low as 0.8V. Dual 40V N-Channel
synchronous MOSFET switches allow for low external com-
ponent thus reducing complexity and minimizing board
space. The LM3100 is designed to work exceptionally well
with ceramic and other very low ESR output capacitors. The
Constant ON-Time (COT) regulation scheme requires no
loop compensation, results in fast load transient response,
and simplifies circuit implementation. Through the use of a
unique design the regulator does not rely on output capacitor
ESR for stability, as do most other COT regulators. The
operating frequency remains nearly constant with line and
load variations due to the inverse relationship between the
input voltage and the on-time. The oprating frequency can
be externally programmed up to 1MHz. Protection features
include V_CC under-voltage lockout, thermal shutdown and
gate drive under-voltage lockout. The part is available in a
thermally enhanced eTSSOP-20 package
Features
n Input voltage range 4.5V - 36V
n 1.5A output current
n 0.8V, ±1.5% reference
n Integrated 40V, dual N-Channel buck synchronous
switches
n Low component count and small solution size
n No loop compensation required
n Ultra-fast transient response
n Stable with ceramic and other low ESR capacitors
n Programmable switching frequency up to 1MHz
n Max. duty cycle limited during start-up
n Valley current limit
n Precision Internal Reference for adjustable output
voltage down to 0.8V
n Thermal shutdown
n Thermally enhanced eTSSOP-20 package
Typical Applications
n 5VDC, 12VDC, 24VDC, 12VAC, and 24VAC systems
n Embedded Systems
n Industrial Controls
n Automotive Telematics and Body Electronics
n Point of Load Regulators
n Storage Systems
n Broadband Infrastructure
n Direct Conversion from 2/3/4 Cell Lithium Batteries
Systems
Typical Application
SIMPLE SWITCHER^® is a registered trademark of National Semiconductor Corporation
© 2006 National Semiconductor Corporation DS201747
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