點晶科技股份有限公司

SILICON TOUCH TECHNOLOGY INC.

ST1115C/ST1115D

SP-ST1115CD-A.005

Version

：A.005

Page

：6

V2)

-

(V1

V

V1)R

-

V2(V

)R

V

-

V1(V2

2

R

DD

T1

DD

T2

DD

+

=

V1

R2)

R

)(

V1

V

(

1

R

T1

DD

+

−

=

Volt, which may slightly vary with the variation of the driving current.

Figure 2. Desired Temperature-Speed Curve

(3) The FGR pin provides the rotation detection output for ST1115C and the tachometer

output for ST1115D. FGR is an open-drain output with a built-in 100k

Ω pullup resistor.

An additional resistor can be used to pull up the FGR voltage to the appropriate level,

which depends on the voltage level of the monitoring/control system.

T1

T2

Temperature

Fan Speed

rpm1

rpm2