F71872
R2
VIN = V+12V
×
R1 + R2
For instance, where V+12V is the analog input voltage.
If we choose R1=27K, R2=5.1K, the exact input voltage for V+12v will be 1.907V, which is within the
tolerance. As for application circuit, it can be refer to the figure shown as follows.
VIN(Lowerthan2.048V)
R1
R2
F71872
D1/D2/D3
VREF
C
2200pF
R
10K, 1%
D1/D2/D3
AGND(D-)
2N3906
Typical Thermister
Connection
10K, 25 C
6.4.2 Temperature Monitoring and Offset
The F71872 can be measured from 0°C to 140°C. The status depends on different situation. As
connected to a BJT thermal diode, detected temperature ranges from 0°C to 140°C without considering the
OFFSET effect. As connected to a thermistor, detected temperature ranges from 0°C to 127°C without
considering the OFFSET effect. The temperature format is as the following table:
Temperature ( High Byte )
Digital Output
0000 0000
0000 0001
0001 1001
0011 0010
0100 1011
0101 1010
0110 0100
1000 1100
0°C
1°C
25°C
50°C
75°C
90°C
100°C
140°C
17
July, 2007
V0.28P
FINTEK [ FEATURE INTEGRATION TECHNOLOGY INC. ]
