C8051F352 Datasheet, PDF (77/234 Pages) Silicon Laboratories – 8 k ISP Flash MCU Family

C8051F350/1/2/3
8. Temperature Sensor
The temperature sensor system consists of two diodes with different temperature properties and two con-
stant current sources. The two channels are connected to the ADC inputs internally, using the ADC’s ana-
log multiplexer. The temperature sensor system can be used in single-ended or differential mode to
measure the temperature of the C8051F350/1/2/3. Single channel measurements produce more output
voltage per degree C, but are not as linear as differential measurements. See Table 8.1 for temperature
sensor electrical characteristics.
The temperature sensor channels are automatically enabled when they are selected by the ADC multi-
plexer. To use the temperature sensor for a single-channel measurement, the ADC multiplexer should be
configured with one channel connected to the temperature sensor, and the other connected to AGND. For
a differential measurement, the temperature sensor should be selected for both ADC channels.
The transfer functions for single-channel and differential measurements are shown in Figure 8.2 and
Figure 8.3, respectively. For slope and offset values, refer to Table 8.1.
AV+
AIN+
Channel
AIN-
Channel
To AIN+ Mux
To AIN- Mux
AGND
Figure 8.1. Temperature Sensor Block Diagram
Table 8.1. Temperature Sensor Electrical Characteristics
V_DD = 3.0 V; –40 to +85 °C unless otherwise specified.
Parameter
Linearity
Offset
Offset Error*
Slope
Slope Error*
AV+ Supply Current
Conditions
Min Typ Max
Single Channel Measurement
— ±0.4 —
Differential Measurement
±0.01
AIN+ Channel Measurement, Temp = 0 °C — 757 —
Differential Measurement, Temp = 0 °C
54.3
—
±1
—
AIN+ Channel Measurement
— –1.73 —
Differential Measurement
205
— ±6.6 —
Single Channel Measurement
—
10
—
Differential Measurement
20
*Note: Represents one standard deviation from the mean.
Units
°C
°C
mV
mV
mV
mV/°C
uV/°C
µV/°C
µA
µA
Rev. 1.1
77