nRF51422 Thermal Characteristics

[Matt Barr]

Where can I find theta JC (junction to case) and theta CA (case to ambient) or equivalent thermal characteristics for the nRF51422 in WLCSP package? I've looked in the data sheet, series reference manual, forum articles and in other downloads from the web site but haven't had any luck finding this information.

Thanks and Best Regards, Matt

[Asbjørn]

Due to their intrinsic low power nature, thermal resistance is generally not a major consideration for Nordic Semiconductor products.

[Matt Barr]

Thanks for the answer, understood. I am definitely not planning to add a heat sink. :-)

I want to use the die temp measurement as a poor-man's ambient temperature sensor, I have a good idea what my average power consumption is and was looking for known-to-be-correct thermal resistance numbers. I can empirically determine a reasonable junction-to-ambient value based on temperature measurements and average power, this should be plenty good enough for what I am trying to do.

[Asbjørn]

It should be fine as long as you don't have to strict requirements for the measurements. I would also recommend you to do a simple calibration of your temperature. We've seen that implementation might change the offset slightly, so test the temperature sensor on your board at a fairly known temperature and check the difference.