45

SLA7042M/SLA7044M

2-Phase Stepper Motor Unipolar Driver ICs (2W1-2 Phase Excitation/Micro-step Support)

SLA7042M/SLA7044M

sInternal Block Diagram

sDiagram of Standard External Circuit

sOutput Current Formula

K: Reference voltage setting rate by serial signal

(See the internal block diagram)

•

3

OUT A OUT B

OUT B

REF A

REF B

GND A GND B

RS A

RS B

712

9

10

3

14

5V

ENABLE

415

1

8

11

18

5

16

2

13

6

17

CLOCK A

CLOCK B

STROBE A

STROBE B

DATA A

DATA B

SLA7042M

SLA7044M

Enable

COMP

Phase

Vref

0%

20%

40%

55.5%

71.4%

83%

91%

100%

a

0

1

0

1

0

1

0

1

PWM

Reset

Ph.

Reset

Enable

COMP

Phase

PWM

Reset

Reset

OFF time timer

(TOFF 3-step switching)

Chopper ON

Noise filter

(2

s)

Latch

Reference voltage

Reference voltage

ab

c

Ph.

Shift register

ab

c

Ph.

Latch

a

b

c

Ph.

a

b

c

Shift register

b

0

0

1

1

0

0

1

1

c

0

0

0

0

1

1

1

1

c

0

0

0

0

1

1

1

1

b

0

0

1

1

0

0

1

1

a

0

1

0

1

0

1

0

1

Vref

0%

20%

40%

55.5%

71.4%

83%

91%

100%

µ

OFF time timer

(TOFF 3-step switching)

Chopper ON

Noise filter

(2

s)

µ