Stepper motor controller for minimal power consumption

New from Allegro MicroSystems, the A3965 is a motor-control integrated circuit for the pulse-width-modulated current control of low voltage
stepper motors.

New from Allegro MicroSystems, the A3965 is a motor-control integrated circuit for the pulse-width-modulated (PWM) current control of low voltage stepper motors.

The A3965S is a DMOS dual full-bridge driver, and is capable of output currents to ±500 mA and operating voltages to 20 V. It is particularly suited to low-power or battery-operated motors where minimal power consumption is desired.

The device is designed for operation from logic supplies of between 2.85 and 5.5 V. The low power consumption is aided by a ‘sleep’ mode which disables all circuitry and typically draws less than 1 µA supply current from motor and logic supply.

During operation, the fixed frequency ‘on’ pulses of each H-bridge within the device are offset 180 degrees out of phase to minimise the peak demand required of the motor supply, allowing savings in size and cost of external power-supply components.

‘Phase’ and ‘enable’ input terminals are provided for use in controlling the speed and direction of a stepper motor with externally applied PWM control signals.

Internal circuit protection includes thermal shutdown with hysteresis, undervoltage monitoring of drive voltage and charge-pump voltage, and crossover current protection. Special power-up sequencing is not required.

The A3965 is supplied in a 24-lead plastic SOIC with a copper batwing tab (suffix LB).

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