STK672-442AN-E Datasheet, PDF (25/27 Pages) ON Semiconductor – 2-phase Stepper Motor Driver

STK672-442AN-E
Overcurrent protection measure: insert a resistor
5V
Reg.
.
VDD=5V
9
MODE1
CLOCK
CWB
RESETB
ENABLE
MODE2
MODE3
VDD
FAO
FABO
FBO
FBBO
A1
B1
Vref
A
AB
B
BB
4
5
3
1
Vcc
R1
R2
C1
24V
Reg
GND
.
2
6
FAULT
Vref
18
S.G
VSS
open
Overcurrent protection measure: insert a diode
Overcurrent path
(4) Input Signal Lines
1) Do not use an IC socket to mount the driver, and instead solder the driver directly to the board to minimize
fluctuations in the GND potential due to the influence of the resistance component and inductance component of
the GND pattern wiring.
2) To reduce noise caused by electromagnetic induction to small signal lines, do not design small signal lines (sensor
signal lines, and 5V or 3.3V power supply signal lines) that run parallel in close proximity to the motor output line
A (Pin 4), AB (Pin 5), B (Pin 3), or BB (Pin 1) phases.
(5) When mounting multiple drivers on a single board
When mounting multiple drivers on a single board, the GND design should mount a VCC decoupling capacitor, C1, for
each driver to stabilize the GND potential of the other drivers. The key wiring points are as follows.
24v
5V
Input
Signals
GND
9
Motor
1
IC1
2
6
19 ¹⁸
Input
Signals
9
Motor
2
IC2
2
6
19 ¹⁸
Input
Signals
9
Motor
3
IC3
2
6
19 ¹⁸
GND
Short
Thick and short
Thick
(6) VCC operating limit
When the output (for example F1) of a 2-phase stepper motor driver is turned OFF, the AB phase back electromotive
force eab produced by current flowing to the paired F2 parasitic diode is induced in the F1 side, causing the output
voltage VFB to become twice or more the VCC voltage. This is expressed by the following formula.
VFB = VCC + eab
= VCC + VCC + IOH x RM + Vdf (1.6V)
VCC: Motor supply voltage, IOH: Motor current set by Vref
No.A2274-25/27