LM2679 Datasheet, PDF (1/37 Pages) National Semiconductor (TI) – SIMPLE SWITCHER 5A Step-Down Voltage Regulator with Adjustable Current Limit

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LM2679
SNVS026O – MARCH 2000 – REVISED JUNE 2016
LM2679 SIMPLE SWITCHER^® 5-A Step-Down Voltage Regulator
With Adjustable Current Limit
1 Features
•1 Efficiency Up to 92%
• Simple and Easy to Design Using Off-The-Shelf
External Components
• Resistor Programmable Peak Current Limit Over a
Range of 3 A to 7 A
• 120-mΩ DMOS Output Switch
• 3.3-V, 5-V, 12-V Fixed Output and Adjustable
(1.2 V to 37 V) Versions
• ±2% Maximum Output Tolerance Over Full Line
and Load Conditions
• Wide Input Voltage Range: 8 V to 40 V
• 260-kHz Fixed Frequency Internal Oscillator
• Soft-Start Capability
• −40 to 125°C Operating Junction Temperature
Range
2 Applications
• Simple-to-Design, High Efficiency (>90%)
Step-Down Switching Regulators
• Efficient System Preregulator for Linear Voltage
Regulators
• Battery Chargers
3 Description
The LM2679 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 5-A 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 3.3 V, 5 V, and 12 V 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
(260 kHz) allows the use of physically smaller sized
components. A family of standard inductors for use
with the LM2679 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 soft-start
timing capacitor to gradually turn on the regulator.
The LM2679 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 specified to a ±2% tolerance. The clock
frequency is controlled to within a ±11% tolerance.
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
TO-263 (7)
10.10 mm × 8.89 mm
LM2679
TO-220 (7)
14.986 mm × 10.16 mm
VSON (14)
6.00 mm × 5.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application
Feedback
0.01 PF
Input
Voltage
8V to 40V
C_IN ^{+ + +}
3 x 15 PF/50V
V_IN
0.47 PF
LM2679 - 5.0
Boost
Softstart
5.6k
1 nF
Current
Limit
Adjust
Switch
Ground ^Output
Output
L
Voltage
22 PH
5V/5A
+
+ _COUT
6TQ045S
2 x 180 PF/16V
I_{CL =}
37,125
R_{ADJ Copyright © 2016, Texas Instruments Incorporated}
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.