A3966: Dual Full-Bridge PWM Motor Driver

Description

The A3966 is designed to drive both windings of a two-phase bipolar stepper motor. The device includes two full-bridges capable of continuous output currents of ±650 mA and operating voltages to 30 V. Motor winding current can be controlled by the internal fixed-frequency, pulse-width modulated (PWM), current-control circuitry. The peak load current limit is set by user selection of a reference voltage and current-sensing resistors.

The fixed-frequency pulse duration is set by a user-selected external RC timing network. The capacitor in the RC timing network also determines a user-selectable blanking window that prevents false triggering of the PWM current-control circuitry during switching transitions.

To reduce on-chip power dissipation, the full-bridge power outputs have been optimized for low saturation voltages. The sink drivers feature the Allegro patented Satlington® output structure. The Satlington outputs combine the low voltage drop of a saturated transistor and the high peak current capability of a Darlington.

For each bridge, a PHASE input controls load-current polarity by selecting the appropriate source and sink driver pair. For each bridge, an ENABLE input, when held high, disables the output drivers. Special power-up sequencing is not required. Internal circuit protection includes thermal shutdown with hysteresis, ground-clamp and flyback diodes, and crossover-current protection.

The A3966 is supplied in a 16-lead plastic wide SOIC with two pins internally fused to the die pad for enhanced thermal dissipation. These pins are at ground potential and need no electrical isolation. The device is lead (Pb) free, with 100% matte tin leadframe plating.

Top Features

  • ±650 mA continuous output current
  • 30 V output voltage rating
  • Internal fixed-frequency PWM current control
  • Satlington® sink drivers
  • User-selectable blanking window
  • Internal ground-clamp and flyback diodes
  • Internal thermal-shutdown circuitry
  • Crossover-current protection and UVLO protection

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A3966SLBTR-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 A3966 is supplied in a 16-lead plastic wide SOIC with two pins internally fused to the die pad for enhanced thermal dissipation. These pins are at ground potential and need no electrical isolation. The device is lead (Pb) free, with 100% matte tin leadframe plating.

 LB-SOIC 24 pin