C8051F360/1/2/3/4/5/6/7/8/9
5.2. Temperature Sensor
The typical temperature sensor transfer function is shown in Figure 5.2. The output voltage (V
) is the
TEMP
positive ADC input when the temperature sensor is selected by bits AMX0P4-0 in register AMX0P.
(mV)
1200
1100
1000
900
VTEMP = Slope*(TEMPC) + Offset mV
800
700
(Celsius)
-50
0
50
100
Figure 5.2. Typical Temperature Sensor Transfer Function
The uncalibrated temperature sensor output is extremely linear and suitable for relative temperature mea-
surements (see Table 5.1 for linearity specifications). For absolute temperature measurements, gain and/
or offset calibration is recommended. Typically a 1-point calibration includes the following steps:
Step 1. Control/measure the ambient temperature (this temperature must be known).
Step 2. Power the device, and delay for a few seconds to allow for self-heating.
Step 3. Perform an ADC conversion with the temperature sensor selected as the positive input
and GND selected as the negative input.
Step 4. Calculate the offset and/or gain characteristics, and store these values in non-volatile
memory for use with subsequent temperature sensor measurements.
Figure 5.3 shows the typical temperature sensor error assuming a 1-point calibration at 25 °C. Note that
parameters which affect ADC measurement, in particular the voltage reference value, will also
affect temperature measurement.
Rev. 1.0
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SILICON [ SILICON ]
