The Allegro A3967 Motor Driver

When I was building my own CNC machines I was using the Allegro 3977 Motor driver IC. Now this chip is rather expensive and a pain to solder . I have built several of those and they are great for big motors up to 2.5Amps. But when I purchased two boxes of smaller stepper motors for my Robotic and CNC projects I realized that those chips were way overkill.

Looking at Allegros website I found the low cost version the Allegro A3967(basically the little brother of the A3977). It is a soic -24 package with a pretty decent pitch. That can be very easily hand soldered .

So I took the schematic from PMINMO.com and modified it fully in SMD to work with my low cost chip A3967.

Now allthough this circuit works . I have tried to miniaturize the first version (working ) with version 2 but never tested that one.

The Allegro A3976 can handle motor currents up to ±750 mA, 30 V Output Rating which is my case plenty. I remember setting my motors to about 330mA . So I could theoreticaly use even bigger motors.

Here are some pictures of the first prototype

And of curse the schematic and layout. The whole project is in the download section or click here.