Unipolar stepper motor driver can drive unipolar motor up to 3.5A and supply range 10 To 50V DC. The board has been designed using STK672-442AEN IC.  The STK672-442AN is a hybrid IC for use as a unipolar, 2-phase stepper motor driver with PWM current control and Micro-stepping.



  • Supply Up to 50V DC Input
  • Logic Supply 5V DC Input
  • Load Current 3.5Amps
  • Stepper Motor: 5 Wires, 6 Wires, 8 Wires (Unipolar)
  • Built-in over current detection function, overheat detection function (Output Off)
  • Fault 1 signal ( Active Low) is output when overcurrent or overheating is detected
  • Fault 2 signal is used to output the result of activation of protection circuit detection at 2 levels.
  • Built-in power on reset function
  • A Micro-step sin wave driven driver can be activated merely by inputting an external clock.
  • The Switch timing of the 4-phase distributor can be switched by setting an external pin (Mode3) to detect either the rise or fall or rise only, of the clock input.
  • The Enable pin can be used to cut output current while maintaining the excitation mode.
  • With a wide current setting range, power consumption can be reduced during standby.


  • No Motor noise during hold mode due to external excitation current control.
  • Incorporating a current detection resistor (0.122Ω: resistor tolerance 2%), motor current can be set using two external resistors.
  • Phase is maintained even when the excitation mode is switched. Rotational direction switching function
  • External pins can be used to select 2, 1-2 (including pseudo-micro), W1-2, 2 W1-2, or 4W1-2 excitation.
  • Clock Input: Input frequency 20Khz when using both edges, Or 50Khz when using one edge
  • Minimum pulse width 20us When using both edge Or 10us when using one edge
  • M3: Jumper J3-Open the excitation phase moves one step at a time at the rising edge of the CLOCK pulse.
  • M3: Jumper J3-Closed the excitation phase moves alternately one step at a time at the rising and falling edges of the CLOCK pulse.
  • Do not Change direction during the 7us interval before and after the rising and falling edges of the CLOCK input.
  • Enable: Normally High for Normal Operation, Pull down control of excitation drive output A, AB, B, and BB, and selecting operation/hold status inside the HIC


CN 1 : Supply Input  up to 50V DC

CN2 : 1 Pin 5V DC, 2 Pin Direction, 3 Pin Clock Input, 4 Pin Enable, 5 Pin GND, 6 NC, 7 Pin FLT2, 8 Pin GND

CN3 : Stepper Motor Connection

D1 LED : Excitation Monitor ( Motor Pulse Indicator)

D3 LED : Power LED


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