23-01-2013, 10:53 AM
LM2576/LM2576HV Series SIMPLE SWITCHER® 3A Step-Down Voltage Regulator
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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 available
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 reduces
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 ±4% tolerance on output
voltage within specified input voltages and output load
conditions, and ±10% on the oscillator frequency. External
shutdown is included, featuring 50 μA (typical) standby current.
The output switch includes cycle-by-cycle current limiting,
as well as thermal shutdown for full protection under
fault conditions.
Features
3.3V, 5V, 12V, 15V, and adjustable output versions
Adjustable version output voltage range,
1.23V to 37V (57V for HV version) ±4% max over
line and load conditions
Guaranteed 3A output current
Wide input voltage range, 40V up to 60V for
HV version
Requires only 4 external components
52 kHz fixed frequency internal oscillator
TTL shutdown capability, low power standby mode
High efficiency
Uses readily available standard inductors
Thermal shutdown and current limit protection
P+ Product Enhancement tested