We are using a TMP75 to monitor ambeint temperature and the front panel board is behind a plastic front panel with no airflow and we are seeing 9-5C increase in temperature do to self heating. Is this normal for this part?
Roger,
This is not normal. What is the quiescent current the part is pulling? Also, what value of pull-up resistors are being used?
Best Regards,Chris FeatherstoneLinear Characterization EngineerHigh Performance Linear Products
The temperature you are reading will be from the ground plane on the printed circuit board (PCB). What other devices are on the PCB? I also want to point out that at a maximum the temperature error will be +/-2oC (for -25o to +85oC) or +/-3oC (for -40o to +125oC) under the specified conditions on page 3 of the datasheet.
It would be expected to see a difference between ambient temperature and the temperature that the device is reading on the ground plane of the PCB especially with other devices heating up the board.