Microchip Technology MIC4574YN

Description
The MIC4574 is a series of fixed and adjustable BICMOS step-down (buck) switch-mode voltage regulators. It operates at a fixed frequency of 200kHz, allowing for a reduction in output filter inductor size compared to the 52kHz LM2574. The MIC4574 is available in 3.3V and 5V fixed output versions, as well as a 1.23V to 20V adjustable output version. It can drive a 0.5A load with excellent line and load regulation. The feedback voltage is guaranteed to ±2% tolerance for adjustable versions, and the output voltage is guaranteed to ±3% for fixed versions. The oscillator frequency is guaranteed to ±10%. In shutdown mode, the regulator draws less than 200μA standby current. It features cycle-by-cycle current limiting and thermal shutdown for protection under fault conditions.

Features
Fixed 200kHz operation
3.3V, 5V, and adjustable output versions
Voltage over specified line and load conditions:
Fixed version: ±3% max. output voltage
Adjustable version: ±2% max. feedback voltage
Guaranteed 0.5A switch current
Wide 4V to 24V input voltage range
Wide 1.23V to 20V output voltage range
Requires minimum external components
<200μA typical shutdown mode
75% efficiency (adjustable version >75% typ.)
Standard inductors and capacitors are 25% of typical LM2574 values
Thermal shutdown
Overcurrent protection
100% electrical thermal limit burn-in

Applications
Simple high-efficiency step-down (buck) regulator
Efficient preregulator for linear regulators
On-card switching regulators
Positive-to-negative converter (inverting buck-boost)
Isolated flyback converter using minimum external components
Negative boost converter