點晶科技股份有限公司

SILICON TOUCH TECHNOLOGY INC.

ST1114C / ST1114L / ST1114M

SP-ST1114CLM-A.008

Version

：A.008

Page

：5

Application Notes

The FGR pin is an open-drained output and outputs the same frequency with HIN pin for

ST1114C, the half frequency of HIN pin for ST1114L, and rotation detection result for

ST1114M. For the rotation detecting output application by ST1114M, the FGR pin, with a

suitable external pull-up resistor, is at logical low state when fan is operating and logical high

state when fan is stopped.

The connection of the capacitance between VDD and GND will increase stability of operation.

The connection of the resistor R1 between VDD and pre-driver will protect device under 12V

operating. For 12V application, the recommended value of this resistor R1 is about 100Ω. For

24V or higher than 12V application, it is recommended that the operating voltage on IC must

be under 12V. As shown on application circuit, it is recommended to connect about 0.5KΩ~1K

Ω resistor R1 and 12Volts Zener Diode DZ between VDD and pre-driver and their values are

dependent on fan applications.

Fan Application

Suggestion for R1

Zener Diode at IC VDD

5V

75Ω

-

12V

100Ω

-

Above 12V(24V,48V)

0.5KΩ~1KΩ

<12V

The period of locking detection and automatic-restart are a little different at different operating

voltage. In normal 12V applications, the lock detection time is about 250ms and auto-restart

time is about 250ms per 2 seconds..

The power dissipated by the IC varies widely with the supply voltage, the output current, and

loading.

It is important to ensure the application does not exceed the allowable power

dissipation of the IC package.

The recommended motor driver power dissipation versus

temperature is depicted as follows:

Power Dissipation-Temperature

0

50

100

150

200

250

300

350

400

0

25

50

75

100

125

150

Ambient Temperature ( ℃ )