I'm not sure that I understand that statement.
By "interface board", are you referring to a "breakout board" or something else?
I neglected to ask whether the motors that you intend to use have 4 wires or perhaps 6 or 8 wires. The answer to that question might have a bearing on the type of driver that would be appropriate. One other parameter of interest would be the motor's winding inductance, which would have a bearing on the drive voltage requirements.
The requirement to handle 3A probably rules out driver circuits such as the Linistepper (
PIC Linear Stepper Motor Controller) or the Easy Stepper Driver (
Easy Driver stepper motor driver).
There have been several schematic posted on this forum for home-made TB6560-based drivers, which should be capable of handling 3A. For example, see the following thread, starting about halfway down the page:
http://www.cnczone.com/forums/diy-cn...cb_mill-2.html. Or, schematics for a Chinese TB6560-based driver are shown on the first page of this thread:
http://www.cnczone.com/forums/genera...y_chinese.html
There has been discussion of drivers capable of handling up to 6A here (although the use of a CPLD makes that approach somewhat of a challenge):
http://www.cnczone.com/forums/open_s...p_bipolar.html
There have been some schematics of drivers based on the L297 and L298 ICs which, IIRC, have a maximum current rating of 3A.
There have been a number of PIC-based driver circuits published, but I don't remember the current handling capabilities of those circuits.