The LM2576-12BU series of monolithic integrated circuits provide all the active functions for a step-down (buck) switching regulator. Fixed versions are available with a 3.3V, 5V, or 12V fixed output. Adjustable versions have an output voltage range from 1.23V to 37V. Both versions are capable of driving a 3A load with excellent line and load regulation.
These regulators are simple to use because they require a minimum number of external components and include internal frequency compensation and a fixed-frequency oscillator.
The LM2576-12BU series offers a high efficiency replacement for popular three-terminal adjustable linear regulators. It substantially reduces the size of the heat sink, and in many cases no heat sink is required.
A standard series of inductors available from several different manufacturers are ideal for use with the LM2576-12BU series. This feature greatly simplifies the design of switch-mode power supplies.
The feedback voltage is guaranteed to ±2% tolerance for adjustable versions, and the output voltage is guaranteed to ±3% for fixed versions, within specified input voltages and output load conditions. The oscillator frequency is guaranteed to±10%. External shutdown is included, featuring less than 200µA standby current. The output switch includes cycle-by-cycle current limiting and thermal shutdown for full protection under fault conditions.
Feature
- 3.3V, 5V, 12V, and adjustable output versions
- Voltage over specified line and load conditions:
- Fixed version: ±3% max. output voltage
- Adjustable version: ±2% max. feedback voltage
- Guaranteed 3A output current
- Wide input voltage range: 4V to 40V
- Wide output voltage range: 1.23V to 37V
- Requires only 4 external components
- 52kHz fixed frequency internal oscillator
- Low power standby mode IQ typically < 200µA
- 80% efficiency (adjustable version typically > 80%)
- Uses readily available standard inductors
- Thermal shutdown and current limit protection
- 100% electrical thermal limit burn-in
