TMP468: Thermal pad (pin17?) on QFN package should this be left floating or connect to GND

Andrew Pettifer

Part Number: TMP468

We are planning on using TMP468AIRGTT temperature seonsor on our product what has Exposed Thermal pad (pin17?) on QFN package but we are unsure it this should this be left floating or connect to GND.

(we have solid GND plane on our board but wanted to confirm we are correct and OK to connect it to GND? This would make most sense in terms of reading the board temperature etc.

These is no mention anywhere in the TMP468 datasheet that it should be tied to GND only that it should be soldered to the PCB

Rgs

Andrew

over 6 years ago

0 Jose Arteaga4 over 6 years ago

TI__Expert 5695 points

Hi Andrew,
Grounding or not your thermal pad will depend on the specific application, e.g. ambient temperature vs. board temperature.
Also for board temp in general you will ground your thermal pad but it also depends on the location of the heat source you want to monitor.
As an starting point I recommend to review the application note listed below, it goes into the details that you may need to take in account:

Temperature Sensors: PCB Guidelines for Surface Mount Devices: www.ti.com/.../snoa967

Regards,
Jose

0 Aaron Heng over 6 years ago in reply to Jose Arteaga4

TI__Mastermind 31600 points

Hi Andrew,

Hopefully, you got all the information you need. Let us know if you need further assistance. I will close this thread.

Aaron

0 Andrew Pettifer over 6 years ago in reply to Aaron Heng

Prodigy 40 points

HI Aaron / Jose

Yes please close this one as have connected to GND in our application. Could I request that a statement as per your email is entered into the datasheet in future for these sort of things as it comes up regularly for thermal pads. Perhaps a reference the app note you pointed me to also?

Thanks again

Kind Regards

Andrew

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TMP468: Thermal pad (pin17?) on QFN package should this be left floating or connect to GND