STK672-050-E

No.5228-7/19

Printed Circuit Board Design Recommendations

This hybrid IC has two grounds, the PG pins (pins 3 and 4) and the SG pin (pin 22). These are connected internally in

the hybrid IC.

Two power supplies are required: a motor drive supply and a 5V supply for the hybrid IC itself. If the ground

connections for these supplies are not good, the motor current waveforms may become unstable, motor noise may

increase, and vibration levels may increase. Use appropriate wiring for these grounds. Here we present two methods for

implementing these ground connections.

If the grounds for the motor drive supply and the hybrid IC 5V supply are connected in the immediate vicinity of the

power supplies:

• If PG and SG are shorted at the power supply, connect only the PG line to pins 3 and 4 on the hybrid IC. Also, be sure

that no problems occur due to voltage drops due to common impedances. In the specifications, this must be VCC2

±5%.

• The current waveforms will be more stable if the Vref ground is connected to pin 22.

• For initial values, use 470μF or over for C1 and 10μF or over for C2.

Locate C1 as close to the hybrid IC as possible, and the capacitor ground line must be as short as possible.

If the grounds for the motor drive supply and the hybrid IC 5V supply are separated:

• Insert a capacitor (C1) of 100μF or over as close as possible to the hybrid IC. The capacitor ground line must be as

short as possible.

The capacitor C2 may be included if necessary. Its ground line should also be as short as possible.

SG

3

4

PG

STK672-050-E

VCC2

Vref

CLK

7

8

22

14

--

+

--

+

SG

PG

C1

+

+

ITF02397

Separation

Motor

drive

power

supply

5V

power

supply

470

μF or over

Stepping motor

Oscillator

circuit

(CLK)

SG

3

4

PG

STK672-050-E

VCC2

Vref

CLK

7

8

22

14

--

+

--

+

SG

PG

C1

+

+

ITF02396

Motor

drive

power

supply

5V

power

supply

470

μF or over

Stepping motor

Oscillator

circuit

(CLK)