Allegro A3977 Microstepping Stepper Motor Control IC Review

Configuration: Dual H-Bridge w/ microstepping translator
Applications: Stepper Motor
Current (peak): 2.5 amps
Voltage (max): 35V
Short circuit protection: No
Built-in chopper current limitation: Yes, Full and half stepping, 4 and 8 microsteps
Interface: Step and Direction

 

A3977 PCB

A3977 PCB

With dual h-bridges and a built-in translator, DAC and chopper circuits, the A3977 is a nearly complete microstepping stepper motor controller on a single chip.  With the addition of a handful of external passive components, this IC is ready to accept step & direction signals from a pulse generator, microcontroller, indexer or CNC controller.  Each pulse applied to the Step input rotates the motor one microstep forward or reverse, depending on the state of the Direction input. 

 

National Semiconductor LMD18245 Motor control IC Review

Configuration: Single H-Bridge
Applications: PM DC, Servo, Stepper
Current (continuous): 3 amps
Current (peak): 6 amps
Voltage (max): 60V
Short circuit protection: Yes
Built-in chopper current limitation: Yes, 4-bit linear DAC
Interface: Parallel
Datasheet: LMD18245

Thanks to its voltage and current capability, the LMD18245 is suitable for driving small PMDC servo motors or a medium size stepper motor winding.  It incorporates a unique lossless current sense output.  This chip also includes a 4-bit linear DAC to generate a reference voltage for the internal chopper circuit.  When used in pairs, these chips can run a stepper motor at up to 8 microsteps per full step with reasonable accuracy.   The LMD18200 is a similar IC that lacks the DAC and chopper circuit.