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LM2670EP
Enhanced Plastic SIMPLE SWITCHER High Efficiency
3A Step-Down Voltage Regulator with Sync
General Description
The LM2670EP series of regulators are monolithic inte-
grated 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 characteris-
tics. 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 adjust-
able 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 inter-
nal 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 LM2670EP 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 LM2670EP series also has built in thermal shutdown,
current limiting and an ON/OFF control input that can power
down the regulator to a low 50A quiescent current standby
condition. The output voltage is guaranteed to a ±2% toler-
ance.
ENHANCED PLASTIC
Extended Temperature Performance of 40C to 125C
Baseline Control - Single Fab & Assembly Site
Process Change Notification (PCN)
Qualification & Reliability Data
Solder (PbSn) Lead Finish is standard
Enhanced Diminishing Manufacturing Sources (DMS)
Support
Features
n
Efficiency up to 94%
n
Simple and easy to design with (using off-the-shelf
external components)
n
150 m
DMOS output switch
n
3.3V, 5V and 12V fixed output and adjustable (1.2V to
37V ) versions
n
50A standby current when switched OFF
n ±
2%maximum output tolerance over full line and load
conditions
n
Wide input voltage range: 8V to 40V
n
External Sync clock capability (280KHz to 400KHz)
n
260 KHz fixed frequency internal oscillator
Applications
n
Simple to design, high efficiency (>90%) step-down
switching regulators
n
Efficient system pre-regulator for linear voltage
regulators
n
Selected Military Applications
n
Selected Avionics Applications
Ordering Information
PART NUMBER
VID PART NUMBER
LM2670SX-ADJEP
V62/04628-01
TS7B
TBD
Note 1: For the following (Enhanced Plastic) versions, check for availability: LM2670SD-12EP, LM2670SD-3.3EP, LM2670SD-5.0EP, LM2670SD-
ADJEP, LM2670SDX-12EP, LM2670SDX-3.3EP, LM2670SDX-5.0EP, LM2670SDX-ADJEP, LM2670T-12EP, LM2670T-3.3EP, LM2670T-5.0EP, LM2670T-
ADJEP, LM2670S-12EP, LM2670S-3.3EP, LM2670S-5.0EP, LM2670S-ADJEP, LM2670SX-12EP, LM2670SX-3.3EP, LM2670SX-5.0EP. Parts listed with an
"X" are provided in Tape & Reel and parts without an "X" are in Rails.
Note 2: FOR ADDITIONAL ORDERING AND PRODUCT INFORMATION, PLEASE VISIT THE ENHANCED PLASTIC WEB SITE AT: www.national.com/
mil
Note 3: Refer to package details under Physical Dimensions
SIMPLE SWITCHER is a registered trademark of National Semiconductor Corporation.
May 2004
LM2670EP
Enhanced
PlasticSIMPLE
SWITCHER
High
Efficiency
3A
Step-Down
V
oltage
Regulator
with
Sync
2004 National Semiconductor Corporation
DS200977
www.national.com