The A4970 motor driver drives both windings of a bipolar stepper motor or bidirectionally controls two DC motors. Both bridges are capable of sustaining 45 V and include internal pulse-width modulation (PWM) control of the output current to 750 mA.
For PWM current control, the maximum output current is determined by user selection of a reference voltage and sensing resistor. Two logic-level inputs select output current limits of 0%, 33%, 67%, or 100% of the maximum level. A PHASE input to each bridge determines load current direction.
Intrinsic diodes in the MOSFET output structure protect against inductive transients. Internally generated delays prevent crossover currents when switching current direction. Special power-up sequencing is not required. Thermal protection circuitry disables the outputs if the chip temperature exceeds safe operating limits.
The device is supplied in a 24-pin surface-mount wide SOIC with two pairs of batwing leads (LB). The webbed-pin construction provides for maximum package power dissipation in the smallest possible construction. The package is lead (Pb) free, with 100% matte tin leadframe plating.