STK673-011-E

No.A1137-7/15

[Hold, CW/CCW]

Hold temporary holds the motor while a phase current of the motor is conducted, even when there are clock inputs of

Low input.

High input releases the hold, and the motor current changes again synchronizing with the rising of Clock signals. Refer

to Timing Chart for exemplary operations.

CW/CCW switches the rotational direction of the motor. Switching to High gives a rotational operation of CW, and

Low gives a rotation operation of CCW. The timing of switching the rotation is synchronizes the rising of the clock

signals. Refer to Timing Chart for exemplary operations.

[Enable]

High input renders a normal operation and Low input forcibly renders a gate signal of MOSFETs Low, thereby cutting

a motor current. Once again High input renders a current to conduct in the motor. The timing of the current does not

synchronize with the clock.

Since Low input of Enable forcibly cuts the motor current, it can be used to cut a V-phase or W-phase while Clock is

maintained in a Low level state after the RESET operation.

Figure 2. Input timings of RESET signal, Enable signal and Clock signal

[Vref (Setting motor current peak value)]

A peak value of a motor current IO is determined by R01, R02, VCC2 (5V) and the following set equation (I).

Set equation of peak value of motor current IO

IO peak = Vref ÷ K

(I)

where

Vref

≤ 0.5 × VCC2

K = 0.63 (V/A)

Vref = VCC2 × Rox ÷ (R01 + Rox)

Rox = (R02

× 4.0kΩ) ÷ (R02 + 4.0kΩ)

• R02 is preferably set to be 100Ω in order to minimize the effect of the internal impedance (4.0kΩ ± 30%) of

STK673-011-E

• K in the above-mentioned set equation varies with in ±5 to ±10% depending on the inductance L and resistance value

R of the used motor. Check the peak value setting of IO upon actual setting.

* Refer to Figure 4 for an example of Vref-IO characteristics

(2) Allowable operating ranges of motor current

Set the peak value of the motor current IO so as to lie within a region below the curve shown in Figure 5 on page 13.

When the operation substrate temperature Tc is set to 105

°C, IO max should be 2.4A or lower and a Hold operation

should be conducted where IO max is 2.0A or lower.

For operation where Tc = 50

°C, IO max should be 4.0A or lower and a Hold operation should be conducted where

IO max is 3.3A or lower.

ITF00810

Enable signal

Rising of 5V power supply

RESET signal input

Clock signal

> 10

μs

> 10

μs

> 1.7ms