LM2670 Datasheet, PDF (1/38 Pages) National Semiconductor (TI) – SIMPLE SWITCHER High Efficiency 3A Step-Down Voltage Regulator with Sync

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LM2670
SNVS036K – APRIL 2000 – REVISED JUNE 2016
LM2670 SIMPLE SWITCHER^® High Efficiency 3-A Step-Down Voltage Regulator With Sync
1 Features
•1 Efficiency Up to 94%
• Simple and Easy to Design With (Using Off-the-
Shelf External Components)
• 150-mΩ DMOS Output Switch
• 3.3-V, 5-V, 12-V Fixed Output and Adjustable
(1.2 V to 37 V) Versions
• 50-µA Standby Current When Switched OFF
• ±2% Maximum Output Tolerance Over Full Line
and Load Conditions
• Wide Input Voltage Range: 8 V to 40 V
• External Sync Clock Capability
(280 kHz to 400 kHz)
• 260-kHz Fixed Frequency Internal Oscillator
• –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
• Communications and Radio Equipment Regulator
With Synchronized Clock Frequency
3 Description
The LM2670 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 3-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
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
(260 kHz) or from an externally provided clock in the
range of 280 kHz to 400 kHz which allows the use of
physically smaller sized components. A family of
standard inductors for use with the LM2670 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 LM2670 series also has built-in thermal
shutdown, current limiting and an ON/OFF control
input that can power down the regulator to a low
50‑µA quiescent current standby condition. The
output voltage is ensured to a ±2% tolerance.
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
TO-263 (7)
10.10 mm × 8.89 mm
LM2670
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
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.