Power Electronics

Programmable Stepper Motor Driver IC

Allegro MicroSystems, Inc. announces a new programmable stepper motor driver IC with improved programmability and diagnostics. The A4979 is a flexible microstepping motor driver with built-in translator for easy operation. It is a single-chip solution, designed to operate bipolar stepper motors in full-, half-, quarter- and sixteenth-step modes, at up to 50 V and 1.5 A. This new device is targeted at the office automation, industrial and consumer markets.

The A4979 can be controlled by simple step and direction inputs, or through the SPI-compatible serial interface. Many of the integrated features as well as diagnostic read back are programmed through the serial port.

The current regulator can be programmed to operate in fixed off-time or fixed frequency PWM, with several decay modes to reduce audible motor noise and increase step accuracy. In addition, phase current tables can be programmed via the serial interface to create unique microstep current profiles to further improve motor performance for specific applications.

Circuit protection includes cross-conduction when switching between high side and low-side drives. The outputs are protected from short circuits. Mixed decay is a key feature integrated within the device to improve low load current accuracy. Other protection includes stall detection and hot and cold thermal warnings, over temperature shutdown, and under voltage lockout.

Allegro's A4979 is available in a 28-pin TSSOP package (suffix LP) with exposed pad for enhanced thermal dissipation. Allegro's A4979 priced at $2.63 in quantities of 1,000.

Allegro Microsystems
Part Number: A4979

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