LM2577N-12                  Description

The LM1577/LM2577 are monolithic integrated circuits that provide all of the power and control functions for step-up (boost), flyback, and forward converter switching regulators. The device is available in three different output voltage versions: 12V, 15V, and adjustable. Requiring a minimum number of external components, these regulators are cost effective, and simple to use. Listed in this data sheet are a family of standard inductors and flyback transformers designed to work with these switching regulators. Included on the chip a 3.0A NPN switch and its associated protection circuitry, consisting of current and thermal limiting, and undervoltage lockout. Other features include a 52 kHz fixed-frequency oscillator that requires no external components, a soft start mode to reduce in-rush current during start-up, and current mode control for improved rejection of input voltage and output load transients.

LM2577N-12                  Features

Requires few external components NPN output switches 3.0A, can stand off 65V Wide input voltage range: to 40V Current-mode operation for improved transient response, line regulation, and current limit n 52 kHz internal oscillator n Soft-start function reduces in-rush current during start-up n Output switch protected by current limit, under-voltage lockout, and thermal shutdown

LM2577N-12                   Applications

n Simple boost regulator n Flyback and forward regulators n Multiple-output regulator

Temperature Range TA +125°C Package Type 24-Pin Surface Mount 16-Pin Molded DIP 5-Lead Surface Mount 5-Straight Leads 5-Bent Staggered Leads 4-Pin TO-3 Output Voltage LM2577S-12 LM2577T-12 Flow LM2577S-15 LM2577T-15 Flow LB03 ADJ LM2577S-ADJ LM2577T-ADJ Flow K04A TO-3 NSC Package Drawing TO-263 TO-220