W83697HFFDC Information Storage Devices, Inc, W83697HFFDC Datasheet - Page 94

• Manufacturer Part Number: W83697HFFDC
• Description: LPC Interface I/o Plus Game/midi Port, Fan Control, Flash ROM I/f
• Manufacturer: Information Storage Devices, Inc

9.3 Analog Inputs
The maximum input voltage of the analog pin is 4.096V because the 8-bit ADC has a 16mv LSB. Really,
the application of the PC monitoring would most often be connected to power suppliers. The CPU V-core
voltage ,+3.3V ,battery and 5VSB voltage can directly connected to these analog inputs. The +12V,-12V
and -5V voltage inputs should be reduced a factor with external resistors so as to obtain the input range.
As Figure 9.2 shows.
9.3.1
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 t han 4.096V for the maximun input
range of the 8 -bit ADC. The Pin 97 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 W83697HF 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.
Monitor over 4.096V voltage:
Negative Input
Positive Input
Typical Thermister Connection
V2
V3
V1
R1
R5
Positive Inputs
R2
1 2
R THM
10K, 25 C
V I N
+12VIN
R3
10K, 1%
R
**The Connections of VTIN1 and VTIN2
Figure. 9.2
AVCC(+5V)
- 85 -
V
+3.3VIN
1
VCOREA
VCOREB
VREF
VTIN3
VTIN2
VTIN1
are same as VTIN3
VBAT
5VSB
R
1
N5VIN
R6
R
Pin 102
Pin 103
Pin 104
2
N12VIN
R
2
R4
Publication Release Date: Feb. 2002
Pin 100
Pin 99
Pin 98
Pin 97
Pin 74
Pin 61
Pin 96
Pin 101
Pin 95
Pin 94
8-bit ADC
16mV LSB
with
W83697HF/F
Revision 0.70