W83783S Information Storage Devices, Inc, W83783S Datasheet - Page 16

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

6.3.1 Monitor over 4.096V voltage:
The input voltage +12VIN can be expressed as following equation.
The value of R1 and R2 can be selected to 28K Ohms and 10K Ohms, respectively, when the input
voltage V1 is 12V. The node voltage of +12VIN can be subject to less than 4.096V for the maximun
input range of the 8-bit ADC. The Pin 24 is connected to the power supply VCC with +5V. There are
two functions in this pin with 5V. The first function is to supply internal analog power in the W83783S
and the second function is that this voltage with 5V is connected to internal serial resistors to monitor
the +5V voltage. The value of two serial resistors are 34K ohms and 50K ohms so that input voltage
to ADC is 2.98V which is less than 4.096V of ADC maximum input voltage. The express equation can
represent as follows.
Negative Input
Positive Input
Typical Thermister Connection
V3
V4
V1
V
in
R1
R7
V C C
12
where VCC is set to 5V.
Positive Inputs
VIN
R2
50
R THM
10K, 25 C
- 11 -
12VIN
Figure 11.
R5
K
10K, 1%
V
R
50
**The connections of VT2
1
K
is same as VT1
VCORE
VDD(+5V)
R
34
+3.3VIN
1
VREF
VT1
R
K
2
R
2
N5VIN
R8
N12VIN
2 98
.
Publication Release Date: April 1999
V
R6
Pin 21
Pin 20
Pin 24
Pin 19
Pin 23
Pin 18
Pin 17
Pin 22
8-bit ADC
16mV LSB
with
W83783S
Preliminary
Revision 0.55