A3966

A3966 Dual Full-Bridge PWM Motor Driver FEATURES AND BENEFITS ▪ ±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 PACKAGE: 16-pin SOICW (suffix LB) Not to scale 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 con...