DMOS Microstepping Driver with Translator and Overcurrent Protection

The A5984 is a complete microstepping motor driver with built-in translator for easy operation. It is designed to operate bipolar stepper motors from full-step up to 1/32 step modes. Step modes are selectable by MSx logic inputs. It has an output drive capacity of up to 40 V and ±2 A.

A5984 introduces a proprietary QuietStep^TM algorithm to optimize the current waveform over a wide range of stepper speeds and stepper motor characteristics. QuietStep^TM adjusts on-the-fly the amount of fast decay during a PWM cycle to keep current ripple at a low level over the various operating conditions. This adaptive feature improves performance of the system resulting in reduced audible motor noise, reduced vibration, and increased step accuracy.

The translator is the key to the easy implementation of the A5984. Simply inputting one pulse on the STEP input drives the motor one microstep. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. The A5984 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened.

The ET package meets customer requirements for no smoke no fire (NSNF) designs by adding no-connect pins between critical output, sense, and supply pins. So, in the case of a pin-to-adjacent-pin short, the device does not cause smoke or fire. Additionally, the device does not cause smoke or fire when any pin is shorted to ground or left open.

Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. Internal circuit protection includes: thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover-current protection. Special power-on sequencing is not required.

The A5984 is supplied in three surface mount packages: two QFN packages, the 4 mm × 4 mm, 0.75 mm nominal overall height ES package, and the 5vmm × 5 mm × 0.90 mm ET package. The LP package is a 24‑pin TSSOP. All three packages have exposed pads for enhanced thermal dissipation, and are lead (Pb) free (suffix –T), with 100% matte-tin-plated leadframes.