General Description

The AZ494B/D is a voltage mode pulse width modulation switching regulator control circuit designed primarily for power supply control.

The AZ494B/D consists of a reference voltage circuit, two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, and an output control circuit. The AZ494B/D is capable for push-pull or single-ended output operation, which can be selected through the output control.

AZ494B has 4.95V and AZ494D has 5V reference voltage respectively. The precision of voltage reference (VREF) is improved up to ± 1.5 through trimming and this provides a better output voltage regulation.

The AZ494B/D is available in standard packages of DIP-16 and SOIC-16.

特性 Features

? Stable 4.95V for AZ494B or 5V for AZ494D Reference Voltage Trimmed to ±1.5 Accuracy

? Uncommitted Output TR for 200mA Sink or Source Current

? Single-End or Push-Pull Operation Selected by Output Control

? Internal Circuitry Prohibits Double Pulse at Either Output

? Complete PWM Control Circuit with Variable Duty Cycle

? On-Chip Oscillator with Master or Slave Operation

Applications

? SMPS

? Back Light Inverter

? Charger