Overview

The STK672-120 is a unipolar fixed-current chopper type 2-phase stepping motor driver hybrid IC. It features power MOSFETs in the output stage and a built-in phase signal distribution IC. The incorporation of a phase distribution IC allows the STK672-120 to control the speed of the motor based on the frequency of an external input clock signal. It supports two types of excitation for motor control: 2-phase excitation and 1-2 phase excitation. It also provides a function for switching the motor direction.

Features

• The motor speed can be controlled by the frequency of an external clock signal (the CLOCK pin signal).

• The excitation type is switched according to the state (low or high) of the MODE pin. The mode is set to 2-phase or 1-2 phase excitation on the rising edge of the clock signal.

• A motor direction switching pin (the CWB pin) is provided.

• All input are Schmitt inputs and 40-kΩ (typical: –50 to

+100) pull-up resistors are built in.

• The motor current can be set by changing the Vref pin voltage. Since a 0.165-Ω current detection resistor is built in, a current of 1 A is set for each 0.165 V of applied voltage.

• The input frequency range for the clock signal used for motor speed control is 0 to 25 kHz.

• Supply voltage ranges: VCC1 = 10 to 42 V, VCC2 = 5.0 V ±5

• This IC supports motor operating currents of up to 2.4 A at Tc = 105°C, and of up to 4.0 A at Tc = 25°C.

Applications

• Two-phase stepping motor drive in send/receive facsimile units

• Paper feed in copiers, industrial robots, and other

applications that require 2-phase stepping motor drive