F71882 Datasheet, PDF (43/130 Pages) Feature Integration Technology Inc. – Super Hardware Monitor + LPC I/O

F71882
(pulse mode)
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(level mode)
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*Interrupt Reset when Interrupt Status Registers are written 1
Voltage SMI# Mode
Fig 7-2
The F71882 monitors three remote temperature sensors. One of these sensors can be
measured from -20°C to 127°C. The others can be measured from 0°C to 145°C (2 Sets) .More
detail please refer register description.
Remote-sensor transistor manufacturers
Manufacturer
Model Number
Panasonic
Philips
2SB0709 2N3906
PMBT3906
Monitor Temperature from “thermistor”
The F71882 can connect three thermistor to measure environment temperature or
remote temperature. The specification of thermistor should be considered to (1) β value is
3435K (2) resistor value is 10K ohm at 25°C. In the Figure 7-1, the thermistor is connected by
a serial resistor with 10K ohm, then connected to VREF.
Monitor Temperature from “thermal diode”
Also, if the CPU, GPU or external circuits provide thermal diode for temperature
measurement, the F71882 is capable to these situations. The build-in reference table is for
PNP 2N3906 transistor. In the Figure 7-1, the transistor is directly connected into temperature
pins.
ADC Noise Filtering
The ADC is integrating type with inherently good noise rejection. Micro-power operation
places constraints on high-frequency noise rejection; therefore, careful PCB board layout and
suitable external filtering are required for high-accuracy remote measurement in electronically
noisy environment. High frequency EMI is best filtered at D+ and D- with an external 2200pF
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May, 2008
V0.28P