By Allegro MicroSystems, LLC 11
The Allegro A4973 is intended as the "next generation" A3953. The most notable design upgrade is the transition from bipolar to DMOS technology. DMOS offers smaller geometries, higher power densities and better switching performance than bipolar technologies.
Designed for bidirectional pulse width modulated (PWM) current control of inductive loads, the A4973 is capable of continuous output currents to ±1.5 A and operating voltages to 50 V. Internal fixed off-time PWM current-control circuitry can be used to regulate the maximum load current to a desired value. The peak load current limit is set by the user's selection of an input reference voltage and external sensing resistor. The fixed off-time pulse duration is set by a user- selected external RC timing network. Internal circuit protection includes thermal shutdown with hysteresis, transient-suppression diodes, and crossover current protection. Special power-up sequencing is not required.