Wearable Temp-Sensing Layout Considerations Optimized for Thermal Response

This application note covers thermal response considerations for sensors that come in a DSBGA package for measuring skin temperature for applications such as wearables such as fitness bands and medical devices.

It will specifically focus on the LMT70, a 0.88mm x 0.88m 0.13°C max accuracy (0.05°C typ) temp sensor over the human body temperature range, but learning can be applied to other temperature sensors that come in a similar package, whether they be analog or digital sensors. Contact temperature sensors, such as the LMT70, need to be placed in close contact with the surface that needs to be measured.

This can be quite challenging for the DSBGA package that is if fast thermal response is also necessary. Experimental results of different PCB layouts will be presented when measuring axillary.