LM2598 pdf,LM2598 datasheet (3

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.
This series of switching regulators is similar to the LM2595
series, with additional supervisory and performance features
added.
Requiring a minimum number of external components, these
regulators are simple to use and include internal frequency
compensation†, improved line and load specifications,
fixed-frequency oscillator, Shutdown /Soft-start, error flag
delay and error flag output.
The LM2598 series operates at a switching frequency of 150
kHz thus allowing smaller sized filter components than what
would be needed with lower frequency switching regulators.
Available in a standard 7-lead TO-220 package with several
different lead bend options, and a 7-lead TO-263 surface
mount package. Typically, for output voltages less than 12V,
and ambient temperatures less than 50°C, no heat sink is
required.
A standard series of inductors (both through hole and surface
mount types) are available from several different manufacturers
optimized for use with the LM2598 series. This
feature greatly simplifies the design of switch-mode power
supplies.
Other features include a guaranteed ±4% tolerance on output
voltage under all conditions of input voltage and output
load conditions, and ±15% on the oscillator frequency. External
shutdown is included, featuring typically 85 μA
standby current. Self protection features include a two stage
current limit for the output switch and an over temperature
shutdown for complete protection under fault conditions.