My stepper motor controller, a Performax 4CX-SA, has open collector outputs for pulse and dir. Performax says these outputs can sink a maximum of 40 mA. Do the Pololu A4983 and TB6612FNG driver carriers sink less than that maximum?
Yes. The inputs on the A4983 will sink only a few tens of micro-amps so they should work with that other product. You can verify this by reading the A4983 datasheet, which is in the first paragraph of the product page for either of our A4983 breakout boards. Look for a table row called “Logic Input Current”.
Also note that since your controller have open collector outputs, you will need pull-up resistors on the STEP and DIR lines. There aren’t any built in to the A4983, and there aren’t any built in to our carrier boards, so you will need to supply your own.