ADIS16355 temperature calculation

Dear Sir/Madam

Please help me please with temperature calculation of ADIS16355.

Real temperature according to external sensor is about 26 °C.

XTEMP_OUT = 0x6d,

YTEMP_OUT = 0x6e

ZTEMP_OUT = 0x58

From datasheet sensor parameters are Output at 25°C 0 LSB, Scale Factor 6.88 LSB/°C

So temperature must be 25°C + (0x6d/6.88) = 40.8°C

Tell me where I'm wrong?

All other registers are read correctly and have the correct data (SUPPLY_OUT, XACCL etc.).

  • 0
    •  Analog Employees 
    on Nov 9, 2012 7:56 PM over 8 years ago

    Hello Fox1,

    Yes, your calculations are correct.  There are two factors that account for the difference in these readings, with respect to your ambient temperature readings.

    1. The power dissipation inside of the ADIS16335 will cause some temperature rise. The Theta-JA (junction to ambient) is 39.8 degrees C/watt. The power dissipation is close to 300mW, so we would expect the temperature rise to be in the range of 10-12 degrees Celsius.
      • Delta-T = 0.057ma x 5V x 39.8 C/W = 11.3 degrees Celsius
    2. The xTEMP_OUT temperature sensors are not calibrated, with respect to ambient conditions. For the most part, we expect the accuracy to be on the order of +/-5C, but there are a number of mechanical factors that can influence this (mounting surface/interface, airflow, etc).

    I hope that helps.  For future reference, the ADIS16365 is the suggested replacement for the ADIS16355, which is no longer in production.