A4973: Full-Bridge PWM Motor Driver

Description

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.

With the ENABLE input held low, the PHASE input controls load current polarity by selecting the appropriate source and sink driver pair. The MODE input determines whether the PWM current-control circuitry operates in a slow current-decay mode (only the selected source driver switching) or in a fast current-decay mode (selected source and sink switching). A user-selectable blanking window prevents false triggering of the PWM current-control circuitry. With the ENABLE input held high, all output drivers are disabled. A sleep mode is provided to reduce power consumption.

When a logic low is applied to the BRAKE input, the braking function is enabled. This overrides ENABLE and PHASE to turn off both source drivers and turn on both sink drivers. The brake function can be used to dynamically brake brush DC motors.

The A4973 is supplied in a choice of two power packages; a 16-pin dual-in-line plastic package with copper heat-sink tabs, and a 16-pin plastic SOIC with copper heat-sink tabs. For both package styles, the power tab is at ground potential and needs no electrical isolation. Each package type is available in a lead (Pb) free version (100% matte tin plated leadframe).

Top Features

  • ±1.5 A continuous output current
  • 50 V output voltage rating
  • 3 V to 5.5 V logic supply voltage
  • Internal PWM current control
  • Fast and slow current-decay modes
  • Sleep (low current consumption) mode
  • Internal transient-suppression diodes
  • Internal thermal shutdown circuitry
  • Crossover current and UVLO protection

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A4973SB-T 16-lead DIP -20°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock
A4973SLBTR-T 16-lead SOIC -20°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.

Packaging

The A4973 is supplied in a choice of two power packages; a 16-pin dual-in-line plastic package with copper heat-sink tabs, and a 16-pin plastic SOIC with copper heat-sink tabs. For both package styles, the power tab is at ground potential and needs no electrical isolation. Each package type is available in a lead (Pb) free version (100% matte tin plated leadframe).

Packages

 

Design Support Tools

Application Notes