Data Sheet

965
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
36.9.8 Temperature Sensor Characteristics
36.9.8.1 Temperature Sensor Characteristics
Note: 1. These values are based on characterization. These values are not covered by test limits in production.
36.9.8.2 Software-based Refinement of the Actual Temperature
The temperature sensor behavior is linear but it depends on several parameters such as the internal voltage reference
which itself depends on the temperature. To take this into account, each device contains a Temperature Log row with
data measured and written during the production tests. These calibration values should be read by software to infer the
most accurate temperature readings possible.
This Software Temperature Log row can be read at address 0x00806030
This section specifies the Temperature Log row content and explains how to refine the temperature sensor output using
the values in the Temperature Log row.
Temperature Log Row
All values in this row were measured in the following conditions:
z V
DDIN
= V
DDIO
= V
DDANA
= 3.3V
z ADC Clock speed = 1MHz
z ADC mode: Free running mode, ADC averaging mode with 4 averaged samples
z ADC voltage reference = 1.0V internal reference (INT1V)
z ADC input = temperature sensor
Table 36-36. Temperature Sensor Characteristics, Device Variant A
(1)
Symbol Parameter Conditions Min. Typ. Max. Units
I
Temperature sensor output
voltage
T= 25°C, V
DDANA
= 3.3V - 0.667 - V
I
Temperature sensor slope 2.3 2.4 2.5 mV/°C
I
Variation over V
DDANA
voltage V
DDANA
=1.62V to 3.6V -1.7 1 3.7 mV/V
I
Temperature Sensor
accuracy
Using the method described in
the “Software-based
Refinement of the Actual
Temperature” on page 965
-10 - 10 °C
Table 36-37. Temperature Sensor Characteristics, Device Variant B
(1)
Symbol Parameter Conditions Min. Typ. Max. Units
I
Temperature sensor output
voltage
T= 25°C, V
DDANA
= 3.3V - 0.688 - V
I
Temperature sensor slope 2.06 2.16 2.26 mV/°C
I
Variation over V
DDANA
voltage V
DDANA
=1.62V to 3.6V -0.4 1.4 3 mV/V
I
Temperature Sensor
accuracy
Using the method described in
the “Software-based
Refinement of the Actual
Temperature” on page 965
-10 - 10 °C