The LM2576 is a 3.0A, 15V, step-down switching regulator designed by National Semiconductor. It is a monolithic integrated circuit that can be used to design a simple and efficient step-down regulator. This circuit has a wide input voltage range and output current range, and only requires 4 external components to complete the circuit design. The circuit uses a 52kHz fixed-frequency internal oscillator and has overtemperature shutdown and current limiting protection.
The LM2576 series provides a monolithic step‑down (buck) regulator capable of delivering up to 3.0 A continuous output current. It is offered in fixed output versions of 3.3 V, 5.0 V, 12 V, 15 V and an adjustable version with an output range of 1.23 V to 37 V. The device operates from a wide input voltage range and requires only four external components.
Typical applications include high‑efficiency power supplies for battery chargers, pre‑regulators for linear regulators, on‑card switching supplies, and buck‑boost converters. The datasheet includes absolute maximum ratings, operating ratings, detailed electrical characteristics, typical performance graphs, and pin function descriptions.
| Maximum Output Current | 3.0 A |
|---|---|
| Fixed Output Voltages | 3.3 V, 5.0 V, 12 V, 15 V |
| Adjustable Output Voltage Range | 1.23 V to 37 V |
| Input Voltage Range | Up to 45 V |
| Switching Frequency | 52 kHz (fixed) |
| Thermal Resistance (J‑A) – TO‑220 | 6.5 °C/W |
The LM2576 can deliver a guaranteed continuous output current of 3.0 A.
The regulator uses a fixed internal oscillator at 52 kHz.
The device is rated for a maximum supply voltage of 45 V.
Fixed output versions are offered at 3.3 V, 5.0 V, 12 V, and 15 V.