LM2576T-ADJ/LF03

Manufacturer Part NumberLM2576T-ADJ/LF03
Description3A STEP-DOWN SIMPLE SWITCHER
ManufacturerNational Semiconductor
LM2576T-ADJ/LF03 datasheet
 
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LM2576/LM2576HV Series
SIMPLE SWITCHER
General Description
The LM2576 series of regulators are monolithic integrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving 3A load with
excellent line and load regulation. These devices are avail-
able in fixed output voltages of 3.3V, 5V, 12V, 15V, and an
adjustable output version.
Requiring a minimum number of external components, these
regulators are simple to use and include internal frequency
compensation and a fixed-frequency oscillator.
The LM2576 series offers a high-efficiency replacement for
popular three-terminal linear regulators. It substantially re-
duces the size of the heat sink, and in some cases no heat
sink is required.
A standard series of inductors optimized for use with the
LM2576 are available from several different manufacturers.
This feature greatly simplifies the design of switch-mode
power supplies.
Other features include a guaranteed
put voltage within specified input voltages and output load
±
conditions, and
10% on the oscillator frequency. External
shutdown is included, featuring 50 µA (typical) standby cur-
rent. The output switch includes cycle-by-cycle current limit-
ing, as well as thermal shutdown for full protection under
fault conditions.
Typical Application
(Fixed Output Voltage
Versions)
SIMPLE SWITCHER
®
is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
3A Step-Down Voltage Regulator
®
Features
n 3.3V, 5V, 12V, 15V, and adjustable output versions
n Adjustable version output voltage range,
1.23V to 37V (57V for HV version)
line and load conditions
n Guaranteed 3A output current
n Wide input voltage range, 40V up to 60V for
HV version
n Requires only 4 external components
n 52 kHz fixed frequency internal oscillator
n TTL shutdown capability, low power standby mode
n High efficiency
n Uses readily available standard inductors
n Thermal shutdown and current limit protection
n P+ Product Enhancement tested
Applications
n Simple high-efficiency step-down (buck) regulator
±
4% tolerance on out-
n Efficient pre-regulator for linear regulators
n On-card switching regulators
n Positive to negative converter (Buck-Boost)
FIGURE 1.
DS011476
August 2004
±
4% max over
01147601
www.national.com