LM2587S-12/NOPB

The LM2587 series regulators are monolithic integrated circuits designed for flyback, boost, and forward converter applications. The device offers 4 different output voltage versions: 3.3V, 5V, 12V, and adjustable voltage. These regulators require minimal external components, making them cost-effective and easy to use. The datasheet includes typical boost and flyback regulator circuits. Selection guides for diodes, capacitors, standard inductors, and flyback transformer series are also provided — these components are specifically intended to work in conjunction with the switching regulators described above. The power switch is a 5A NPN device capable of switching 65V. The power switch is protected by current and thermal limiting circuits as well as an undervoltage lockout circuit. This IC incorporates a 100kHz fixed-frequency internal oscillator, which allows the use of small magnetics. Additional features include a soft-start mode to reduce inrush current during startup, current-mode control for improved rejection of input voltage and output load transients, and cycle-by-cycle current limiting. Under rated input voltage and output load conditions, the power supply system ensures an output voltage tolerance of ±4%.

Applications

• Flyback regulator
• Multiple-output regulator
• Simple boost regulator
• Forward converter

Key features

• No external components required
• Standard inductor and transformer series
• NPN output switching current of 5A, capable of switching off 65V
• Wide input voltage range: 4V to 40V
• Current mode operation for improved transient response, line regulation, and current limiting
• 100kHz switching frequency
• Internal soft-start function reduces inrush current during startup
• Output transistor protection via current limiting, undervoltage lockout, and thermal shutdown
• Maximum system output voltage tolerance of ±4% across varying line and load conditions
• Create custom designs using LM2587 with WEBENCH Power Designer