LM2677SD-ADJ Datasheet, PDF (1/34 Pages) Texas Instruments – LM2677 SIMPLE SWITCHER® High Efficiency 5A Step-Down Voltage Regulator

LM2677
www.ti.com
SNVS077I – MAY 2004 – REVISED JUNE 2012
LM2677 SIMPLE SWITCHER® High Efficiency 5A Step-Down Voltage Regulator with Sync
Check for Samples: LM2677
FEATURES
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•23 Efficiency up to 92%
• Simple and Easy to Design with (Using Off-the-
shelf External Components)
• 100 mΩ DMOS Output Switch
• 3.3V, 5V and 12V Fixed Output and Adjustable
(1.2V to 37V ) Versions
• 50μA Standby Current when Switched OFF
• ±2%maximum Output Tolerance Over Full Line
and Load Conditions
• Wide Input Voltage Range: 8V to 40V
• External Sync Clock Capability (280KHz to
400KHz)
• 260 KHz Fixed Frequency Internal Oscillator
• −40 to +125°C Operating Junction Temperature
Range
APPLICATIONS
• Simple to Design, High Efficiency (>90%) Step-
down Switching Regulators
• Efficient System Pre-regulator for Linear
Voltage Regulators
• Battery Chargers
• Communications and Radio Equipment
Regulator with Synchronized Clock Frequency
DESCRIPTION
The LM2677 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 5A 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. The switching clock frequency can be
provided by an internal fixed frequency oscillator
(260KHz) or from an externally provided clock in the
range of 280KHz to 400Khz which allows the use of
physically smaller sized components. A family of
standard inductors for use with the LM2677 are
available from several manufacturers to greatly
simplify the design process. The external Sync clock
provides direct and precise control of the output ripple
frequency for consistent filtering or frequency
spectrum positioning.
The LM2677 series also has built in thermal
shutdown, current limiting and an ON/OFF control
input that can power down the regulator to a low
50μA quiescent current standby condition. The output
voltage is ensured to a ±2% tolerance.
Typical Application
Input
Voltage
8V to 40V
+++
3 x 15 PF/50V
V_IN
0.47 PF
Feedback
0.01 PF
LM2677 - 5.0
Boost
1 k:
Switch
Ground Output
L
22 PH
6TQ045S
Output
Voltage
5V/5A
2 x 180 PF, 16V
Optional External
Sync Clock
(280 kHz to 400 kHz)
100 pF
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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 is a trademark of Texas Instruments.
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All other trademarks are the property of their respective owners.
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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.
Copyright © 2004–2012, Texas Instruments Incorporated