lm2675ldx-12 National Semiconductor Corporation, lm2675ldx-12 Datasheet
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lm2675ldx-12
Manufacturer Part Number
lm2675ldx-12
Description
Simple Switcher Power Converter High Efficiency 1a Step-down Voltage Regulator
Manufacturer
National Semiconductor Corporation
Datasheet
1.LM2675LDX-12.pdf
(26 pages)
© 2005 National Semiconductor Corporation
LM2675
SIMPLE SWITCHER
1A Step-Down Voltage Regulator
General Description
The LM2675 series of regulators are monolithic integrated
circuits built with a LMDMOS process. These regulators
provide all the active functions for a step-down (buck)
switching regulator, capable of driving a 1A load current with
excellent line and load regulation. These devices are avail-
able in fixed output voltages of 3.3V, 5.0V, 12V, and an
adjustable output version.
Requiring a minimum number of external components, these
regulators are simple to use and include patented internal
frequency compensation (Patent Nos. 5,382,918 and
5,514,947) and a fixed frequency oscillator.
The LM2675 series operates at a switching frequency of
260 kHz, thus allowing smaller sized filter components than
what would be needed with lower frequency switching regu-
lators. Because of its very high efficiency (
per traces on the printed circuit board are the only heat
sinking needed.
A family of standard inductors for use with the LM2675 are
available from several different manufacturers. This feature
greatly simplifies the design of switch-mode power supplies
using these advanced ICs. Also included in the datasheet
are selector guides for diodes and capacitors designed to
work in switch-mode power supplies.
Other features include a guaranteed
output voltage within specified input voltages and output
load conditions, and
ternal shutdown is included, featuring typically 50 µA
stand-by current. The output switch includes current limiting,
as well as thermal shutdown for full protection under fault
conditions.
Typical Application
SIMPLE SWITCHER
Windows
®
is a registered trademark of Microsoft Corporation.
®
is a registered trademark of National Semiconductor Corporation.
±
10% on the oscillator frequency. Ex-
±
DS012803
1.5% tolerance on
®
>
90%), the cop-
Power Converter High Efficiency
To simplify the LM2675 buck regulator design procedure,
there exists computer design software, LM267X Made
Simple version 6.0.
Features
n Efficiency up to 96%
n Available in SO-8, 8-pin DIP and LLP packages
n Computer Design Software LM267X Made Simple
n Simple and easy to design with
n Requires only 5 external components
n Uses readily available standard inductors
n 3.3V, 5.0V, 12V, and adjustable output versions
n Adjustable version output voltage range: 1.21V to 37V
n
n Guaranteed 1A output load current
n 0.25Ω DMOS Output Switch
n Wide input voltage range: 8V to 40V
n 260 kHz fixed frequency internal oscillator
n TTL shutdown capability, low power standby mode
n Thermal shutdown and current limit protection
Typical Applications
n Simple High Efficiency (
n Efficient Pre-Regulator for Linear Regulators
n Positive-to-Negative Converter
(version 6.0)
conditions
Regulator
±
1.5% max output voltage tolerance over line and load
>
90%) Step-Down (Buck)
01280301
www.national.com
June 2005