TMC2100 Stepper Driver 1 stk.

TMC2100

Driver-IC: TMC2100, noiseless operation (in certain modes)
Motor voltage: 5 to 45VDC
Hardware compatible with Step Stick and Pololu A4988
1.25A RMS continuous current (equivalent to about 1,77A Imax)
Step Pulse/Direction interface with micro-step function (interpolation of up to 256 micro-steps)
The driver board is "upside down" mounted, with the chip and the potentiometer down. Very important to make sure Not mounting wrong. To allow this, the pinout is mirrored too.
The heat sink is mounted on the circuit board on the back. This is much better, because the heat is much better guided by the heat pipes of the board, than the thick plastic layer of the chip itself.
The best way to adjust the motor current, the voltage at Vref-Pin (0 - 2,5V)to measure and then adjust the potentiometer. The maximum continuous current is 1,25A (Irms) or 1,77A (Imax) and is determined by the 0,11Ω-sense resistor.
Formulas for calculating the values:
Irms = (Vref * 1.77A) / 2.5V
Irms = Vref * 0.71
Imax = 1.41 * Irms
Vref = (Irms * 2.5V) / 1.77A
Vref = Irms * 1.41
Vref = Imax

Example: A voltage of 1.0V at the VREF pin sets the motor current to 0,71A Irms / 1A Imax.
Vref = (Irms * 2.5V) / 1.77A
1V = (0,71A * 2.5V) / 1.77A