Programmable stepper-motor driver IC offers improved programmability and diagnostics

The A4979 uses all digital timing, with no need for external timing components, and utilizes a serial port (SPI) for programming operating parameters and reading back diagnostic information. The device can be controlled by simple step and direction inputs or through the SPI-compatible serial interface.

The current regulator can be programmed to operate in fixed off-time or fixed frequency pulse-width modulation modes, with several decay modes available to reduce audible motor noise and increase step accuracy. In addition, phase current tables can be programmed via the serial interface to create unique microstepping 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 features include stall detection and hot and cold thermal warnings, overtemperature shutdown and undervoltage lockout.

This new device is targeted at the office automation, industrial and consumer markets.

The A4979 is available in a 28-pin TSSOP package (suffix LP) with exposed pad for enhanced thermal dissipation.