AR0331 datasheet(45/72 Pages) ONSEMI

45 / 72 page

AR0331_DS Rev. L Pub. 5/15 EN

©Semiconductor Components Industries, LLC, 2015.

AR0331: 1/3-Inch 3.1 Mp/Full HD Digital Image Sensor

Changing Sensor Modes

Temperature Sensor

The AR0331 sensor has a built-in PTAT-based temperature sensor, accessible through

registers, that is capable of measuring die junction temperature.

The temperature sensor can be enabled by writing R0x30B4[0]=1 and R0x30B4[4]=1.

After this, the temperature sensor output value can be read from R0x30B2[9:0].

The value read out from the temperature sensor register is an ADC output value that

needs to be converted downstream to a final temperature value in degrees Celsius. Since

the PTAT device characteristic response is quite linear in the temperature range of oper-

ation required, a simple linear function in the format of the equation below can be used

to convert the ADC output value to the final temperature in degrees Celsius.

(EQ 9)

For this conversion, a minimum of two known points are needed to construct the line

formula by identifying the slope and y-intercept “T0”. These calibration values can be

read from registers R0x30C6 and R0x30C8, which correspond to value read at 70°C and

55°C respectively. Once read, the slope and y-intercept values can be calculated and

used in Equation 9.

For more information on the temperature sensor registers, refer to the AR0331 Register

Reference.

Temperature

slope

R0x30B2 9:0

 T



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