The LM2591HV series operates at a switching frequency
of150 kHz thus allowing smaller sized filter com-pontents
than what would be needed with lower frequency switching
regulators. Available in a standard 5-lead TO-220 package
with several different lead bend options, and a 5-lesd
TO-263 surface mount package.
The LM2591HV series of regulators are monolithicintegrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving a 1A load with
excellent line and load regulation. These devices are
available in fixed output voltages of 3.3V, 5V, 12V, and an
adjustable output version.
General Description
Requiring a minimum number of external components, these
regulators are simple to use and include internal frequency
compensation†, and a fixed-frequency oscillator.
A standard series of inductors are available from several
different manufacturers optimized for use with the LM2591
series. This feature greatly simplifies the design of
switch-mode power supplies.
Other features include a guaranteed ±4% tolerance on output
voltage under specified input voltage and output load
conditions, and ±15% on the oscillator frequency. External
shutdown is included, featuring typically 80 μA standby current.
Self protection features include a two stage frequency
reducing current limit for the output switch and an over
temperature shutdown for complete protection under fault
conditions.

Available in TO-220 and TO-263 packages
(57V for HV version)
Features
n 3.3V, 5V, 12V, and adjustable output versions
n Adjustable version output voltage range, 1.2V to 57V
±4% max over line and load conditions
n
n Guaranteed 1A output load current
n Input voltage range up to 60V
n Requires only 4 external components
n Excellent line and load regulation specifications
n 150 kHz fixed frequency internal oscillator
n TTL shutdown capability
n Low power standby mode, IQ typically 80 μA
n High efficiency
n Uses readily available standard inductors
n Thermal shutdown and current limit protection
Applications
n Simple high-efficiency step-down (buck) regulator
n On-card switching regulators
n Positive to negative converter