The LM1577/LM2577 is a simple switch regulator that provides up to 3.0A of output current. The input voltage range is 3.5V to 40V. The device features overcurrent protection, undervoltage protection, and thermal shutdown.
The LM1577 and LM2577 are monolithic integrated circuits that provide power and control functions for step‑up (boost), flyback, and forward converter switching regulators. They include a 3.0 A NPN output switch, internal 52 kHz oscillator, soft‑start, and current‑mode control, requiring few external components.
The devices are offered in multiple package styles (TO‑220, TO‑263, DIP, etc.) and output‑voltage versions (12 V, 15 V, adjustable). Typical applications include simple boost regulators, flyback and forward converters, and multi‑output regulators. Absolute maximum ratings, electrical characteristics, thermal parameters, and physical dimensions are provided for design reference.
| Oscillator Frequency | 52 kHz |
|---|---|
| NPN Output Switch Current | 3.0 A |
| Supply Voltage (Maximum) | 45 V |
| Output Switch Voltage | 65 V |
| Output Switch Current (Limit) | 6.0 A |
| Thermal Resistance (J‑A) – K Package | 35 °C·W⁻¹ |
The device uses a fixed‑frequency oscillator of 52 kHz.
The absolute maximum supply voltage is 45 V.
The output switch is rated for up to 65 V.
The NPN output switch can handle 3.0 A continuous current.