SNVS030N – APRIL 2000 – REVISED APRIL 2013
LM2673 SIMPLE SWITCHER
®
3A Step-Down Voltage Regulator with Adjustable Current
Limit
Check for Samples:
1
FEATURES
Efficiency Up to 94%
Simple and Easy to Design with (Using Off-
The-Shelf External Components)
Resistor Programmable Peak Current Limit
Over a Range of 2A to 5A
150 mΩ DMOS Output Switch
3.3V, 5V and 12V Fixed Output and Adjustable
(1.2V to 37V) Versions
±2% Maximum Output Tolerance Over Full
Line and Load Conditions
Wide Input Voltage Range: 8V to 40V
260 KHz Fixed Frequency Internal Oscillator
Softstart Capability
−40
to +125°C Operating Junction Temperature
Range
DESCRIPTION
The LM2673 series of regulators are monolithic
integrated circuits which provide all of the active
functions for a step-down (buck) switching regulator
capable of driving up to 3A loads with excellent line
and load regulation characteristics. High efficiency
(>90%) is obtained through the use of a low ON-
resistance DMOS power switch. The series consists
of fixed output voltages of 3.3V, 5V and 12V and an
adjustable output version.
The SIMPLE SWITCHER
®
concept provides for a
complete design using a minimum number of external
components. A high fixed frequency oscillator
(260KHz) allows the use of physically smaller sized
components. A family of standard inductors for use
with the LM2673 are available from several
manufacturers to greatly simplify the design process.
Other features include the ability to reduce the input
surge current at power-ON by adding a softstart
timing capacitor to gradually turn on the regulator.
The LM2673 series also has built in thermal
shutdown and resistor programmable current limit of
the power MOSFET switch to protect the device and
load circuitry under fault conditions. The output
voltage is ensured to a ±2% tolerance. The clock
frequency is controlled to within a ±11% tolerance.
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APPLICATIONS
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Simple to Design, High Efficiency (>90%) Step-
Down Switching Regulators
Efficient System Pre-Regulator for Linear
Voltage Regulators
Battery Chargers
Typical Application
Feedback
0.01
PF
Input
Voltage
8V to 40V
C
IN
2 x 15
PF/50V
+
+
Softstart
8.2k
1 nF
Current
Limit
Adjust
V
IN
0.47
PF
LM2673 - 5.0
Boost
L
33
PH
SR305
Output
Voltage
5V/3A
+ C
OUT
180
PF/16V
Switch
Ground Output
I
CL
=
37,125
R
ADJ
1
2
3
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SIMPLE SWITCHER, Switchers Made Simple are registered trademarks of Texas Instruments.
All other trademarks are the property of their respective owners.
Copyright © 2000–2013, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
TI [ TEXAS INSTRUMENTS ]
