STK672-120-E Datasheet, PDF (4/9 Pages) Sanyo Semicon Device – Thick-Film Hybrid IC Unipolar Fixed-Current Chopper (Self-Excited PWM) Scheme and Built-in Phase Signal Distribution IC Two-Phase Stepping Motor Driver (Square Wave Drive) Output Current 2.4A

Sample Application Circuit
STK672-120-E
VDD=5V
CLOCK
MODE
CWB
5V
RO3
D1
+
CO4 10μF
STK672-120-E
10μF
CO3 ^{+ 10}
9
8
7
A
5
AB
4
Two-phase stepping motor
RESETB
6
5V
B
3
BB
2
RO1
Vref
RO2
0.1μF
CO1
12
11
GND
1
VCC
24V
+ _CO2
At least 100μF
P.GND
ITF02597
• To minimize noise in the 5V system, locate the ground side of capacitor CO2 in the above circuit as close as possible
to pin 1 of the IC.
• Insert resistor RO3 (47 to 100Ω) so that the discharge energy from capacitor CO4 is not directly applied to the CMOS
IC in this hybrid device. If the diode D1 has Vf characteristics with Vf less than or equal to 0.6V (when If = 0.1A),
this will be smaller than the CMOS IC input pin diode Vf. If this is the case RO3 may be replaced with a short
without problem.
• Standard or HC type input levels are used for the pin 7, 8, and 9 inputs.
• If open-collector type circuits are used for the pin 7, 8, and 9 inputs, these circuit will be in the high-impedance state
for high level inputs. As a result, chopping circuit noise may cause the input circuits to operate incorrectly. To prevent
incorrect operation due to such noise, capacitors with values between 470 and 1000pF must be connected between
pins 7 and 11, 8 and 11, and 9 and 11. (A capacitor with a value between 470 and 1000pF must be connected between
pins 6 and 11 as well if an open-collector output IC is used for the RESETB pin (pin 6) input.)
• Taking the input bias current (IIB) characteristics into account, the resistor RO1 must not exceed 100kΩ.
• The following circuit (for a lowered current of over 0.2A) is recommended if the application needs to temporarily
lower the motor current. Here, a value of close to 100kΩ must be used for resistor RO1 to make the transistor output
saturation voltage as low as possible.
5V
5V
RO1
RO3
Vref
RO2
RO1
Vref
RO3
RO2
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