W83782G Nuvoton Technology Corporation of America, W83782G Datasheet - Page 16

• Manufacturer Part Number: W83782G
• Description: IC MONITOR H/W 48-LQFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83782G

• Output Type: I²C™, ISA
• Function: Hardware Monitor
• Topology: ADC, Fan Speed Counter, Register Bank
• Sensor Type: External
• Sensing Temperature: External Sensor
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Temperature Sensor Function: Temp Sensor
• Operating Temperature (min): -40C
• Operating Temperature (max): 120C
• Operating Supply Voltage (typ): 5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Where the
VREF=3.6V and the parameter
6.3.3 Monitor temperature from thermistor
The W83782D/G can connect three thermistors to measure three different envirment temperatures.
The specification of thermistor should be considered to (1) β value is 3435K, (2) resistor value is 10K
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 W83782D/G 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 PIITDx in the
W83782D/G. 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 together to act as a thermal diode.
β
is set to 120K/(120K+56K). If the monitored ADC value in the N5VIN channel is 0.8635,
V
6
=
N VIN VREF
Temperature Sensor
Bipolar Transistor
Pentium II
Therminal
5
CPU
B
Diode
OR
C
E
2N3904
1
−
β
−
γ
is 0.6818 then the negative voltage of V6 can be evalated to be -5V.
D+
D-
×
γ
Figure 12.
R=30K, 1%
TM
- 13 -
thermal diode or bipolar transistor 2N3904
R=30K, 1%
C=3300pF
C=3300pF
TM
(Deschutes) thermal diode interface or
Publication Release Date: April 14, 2005
VREF
PIITDx
PIITDx
W83782D/W83782G
W83782D
Revision 2.0
TM
D- is