The LM2587 series of regulators are monolithic integrated circuits specifically designed
for flyback, step-up (boost), and forward converter applications. The device is available in 4
different output voltage versions: 3.3 V, 5 V, 12 V, and adjustable.Requiring a minimum number of external components, these regulators are cost effective,
and simple to use. Included in the datasheet are typical circuits of boost and flyback regulators.
Also listed are selector guides for diodes and capacitors and a family of standard inductors and
flyback transformers designed to work with these switching regulators.The power switch is a 5-A NPN device that can stand-off 65 V. Protecting the power switch
are current and thermal limiting circuits, and an undervoltage lockout circuit. This IC contains a
100 kHz fixed-frequency internal oscillator that permits the use of small magnetics. Other features
include soft-start mode to reduce in-rush current during start up, current mode control for
improved rejection of input voltage and output load transients and cycle-by-cycle current limiting.
An output voltage tolerance of ±4%, within specified input voltages and output load conditions, is
ensured for the power supply system.
