TEMP_OUT Variation

Q:

The TEMP_OUT reading is quite a bit higher than the ambient temperature.  Is this normal?

A:

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Yes, this is normal.  Here are some key points to consider:

• Using Theta-JA and power dissipation, one can compute the estimated temperature rise in the hottest junction inside of the ADIS16xxx devices.  For example, on the ADIS16485
  • Power Dissipation = 3.3V x 0.197A = 0.65W (ADIS16485 Datasheet, Rev C, Table 1, Page 5)
  • Theta-JA = 22.8 C/W (ADIS16485 Datasheet, Rev C, Table 4, Page 7)
  • Estimated temperature rise = 0.65W x 22.8 C/W = 14.8 C
• TEMP_OUT is not calibrated for any specific mounting configuration, airflow or other local thermal influences.
• TEMP_OUT's primary function is to be a relative control variable in the device's internal thermal calibration
• TEMP_OUT accuracy, at the internal point of measurement = +/-10C
• Therefore, observing TEMP_OUT at +25C above the ambient temperature is possible.

We hope that this helps!