W83783S Information Storage Devices, Inc, W83783S Datasheet - Page 18

• Manufacturer Part Number: W83783S
• Description: H/w Monitor: 3 Temp.(thermal Diode), 6 Vol., 2 PWM Fan Control
• Manufacturer: Information Storage Devices, Inc

6.3.3 Monitor temperature from thermistor:
The W83783S can connect three thermistors to measure three different envirment temperature. The
specification of thermistor should be considered to (1)
ohms at 25 C. In the Figure 11, the themistor is connected by a serial resistor with 10K Ohms, then
connect to VREF (Pin 37).
6.3.4 Monitor temperature from Pentium II
The W83783S can alternate the thermistor to Pentium II
transistor 2N3904 and the circuit connection is shown as Figure 12. The pin of Pentium II
connected to power supply ground (GND) and the pin D+ is connected to pin PIIx in the W83783S.
The resistor R=30K ohms should be connected to VREF to supply the diode bias current and the
bypass capacitor C=3300pF should be added to filter the high frequency noise. The transistor 2N3904
should be connected to a form with a diode, that is, the Base (B) and Collector (C) in the 2N3904
should be tied togeter to act as a thermal diode.
Temperature Sensor
Bipolar Transistor
Pentium II
Therminal
CPU
B
Diode
OR
C
E
2N3904
D+
D-
Figure 12.
TM
- 13 -
R=30K, 1%
thermal diode or bipolar transistor 2N3904
R=30K, 1%
C=3300pF
C=3300pF
TM
value is 3435K, (2) resistor value is 10K
(Deschutes) thermal diode interface or
VREF
PIITDx
PIITDx
W83783S
Publication Release Date: April 1999
W83783S
Preliminary
Revision 0.55
TM
D- is