NATIONAL SEMICONDUCTOR LM1575 LM2575 LM2575HV Owner's Manual
Summary
This technical resource details the LM1575/LM2575/LM2575HV series, highly efficient simple switcher step-down voltage regulators (buck converters). Engineered for diverse power supply applications, these regulators provide stable, adjustable output voltages (3.3V to 15V) and are capable of handling 1A loads. The manual provides comprehensive details on features—such as high efficiency, wide input ranges, internal compensation, and various physical packages—making it an essential guide for electrical engineers designing compact, reliable switching power solutions.
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April 2007
LM1575/LM2575/LM2575HV SIMPLE SWITCHER® 1A Step-Down Voltage Regulator General Description Features The LM2575 series of regulators are monolithic integrated 3.3V, 5V, 12V, 15V, and adjustable output versions circuits that provide all the active functions for a step-down
Adjustable version output voltage range,
(buck) switching regulator, capable of driving a 1A load with
1.23V to 37V (57V for HV version) ±4% max over
excellent line and load regulation. These devices are avail-
line and load conditions
able in fixed output voltages of 3.3V, 5V, 12V, 15V, and an
Guaranteed 1A output current
adjustable output version.
Wide input voltage range, 40V up to 60V for HV version
Requiring a minimum number of external components, these
Requires only 4 external components
regulators are simple to use and include internal frequency
compensation and a fixed-frequency oscillator. 52 k Hz fixed frequency internal oscillator The LM2575 series offers a high-efficiency replacement for TTL shutdown capability, low power standby mode
popular three-terminal linear regulators. It substantially re- High efficiency duces the size of the heat sink, and in many cases no heat
Uses readily available standard inductors
sink is required.
Thermal shutdown and current limit protection
A standard series of inductors optimized for use with the
P+ Product Enhancement tested
LM2575 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode pow-
er supplies. Applications
Other features include a guaranteed ±4% tolerance on output Simple high-efficiency step-down (buck) regulator voltage within specified input voltages and output load con-
Efficient pre-regulator for linear regulators
ditions, and ±10% on the oscillator frequency. External shut-
On-card switching regulators
down is included, featuring 50 μA (typical) standby current.
Positive to negative converter (Buck-Boost)
The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault con- ditions.
Typical Application (Fixed Output Voltage Versions)
Note: Pin numbers are for the TO-220 package.
SIMPLE SWITCHER® is a registered trademark of National Semiconductor Corporation
© 2007 National Semiconductor Corporation www.national.com
Page Summary Contents For NATIONAL SEMICONDUCTOR LM1575 LM2575 LM2575HV Owner's Manual
Manual Details
| Brand | National |
|---|---|
| Pages | 28 |
| File Size | 856.67 KB |
| Published | July 16, 2026 |
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Frequently Asked Questions
What is the primary advantage of using this step-down regulator over traditional linear regulators?
It is a high-efficiency (buck) switch-mode regulator that substantially reduces the size required for heat sinks, and in many cases, no heat sink is needed.
What are the available fixed output voltages if I do not need an adjustable version?
Fixed versions are typically available at 3.3V, 5V, 12V, and 15V.
What types of protection does the regulator offer to prevent circuit failure?
It includes thermal shutdown, current limit protection, và TTL shutdown capability for full protection under fault conditions.
How many external components are required for implementation?
These regulators minimize complexity and require only a minimum number of four external components, including standard available inductors.