LM2578A/LM3578A,pdf datasheet

The LM2578A is a switching regulator which can easily be
set up for such DC-to-DC voltage conversion circuits as the
buck, boost, and inverting configurations. The LM2578A features
a unique comparator input stage which not only has
separate pins for both the inverting and non-inverting inputs,
but also provides an internal 1.0V reference to each input,
thereby simplifying circuit design and p.c. board layout. The
output can switch up to 750 mA and has output pins for its
collector and emitter to promote design flexibility. An external
current limit terminal may be referenced to either the ground
or the Vin terminal, depending upon the application. In addition,
the LM2578A has an on board oscillator, which sets the
switching frequency with a single external capacitor from <1
Hz to 100 kHz (typical).