Difference count on MBR3116 does not return to 0 occasionally when object is removed from proximity sensor

[mibrc_3372801]

I'm bringing up a design that uses a single proximity loop (PS0) to detect if an object is present. The loop is a copper trace on top of a 4 layer PCB. I have followed all the design parameters and the proximity sensor appears to work well. I am able to detect objects reliably.

The problem is that occasionally when an object has been left on top of the proximity loop for ~10-20 minutes and then removed the sensor button status stays "on". I can see via EZ-Click that the difference count is still saturated around ~300 counts.

I have several boards and have noticed this at least three different times on three different PCBAs, so I believe this is a configuration setting or something with the algorithm internal to the PSoC.

Could this be a function of the low pass filter? Is the chip auto-adjusting the baseline up since the object is present for a long while? Are there specific parameters I should be looking at adjusting to mitigate or stop this from happening?

Any help is appreciated.

[BragadeeshV]

Hi Michael,

Can you please check if you have enabled the Proximity Auto reset feature? If you have enabled it, try disabling it and check it once again. Post your results here.

Regards,

Bragadeesh

[mibrc_3372801]

Hello Bragadeesh,

I do not have Proximity Auto reset enabled.

Here are the settings I am using:

Thank you.

[BragadeeshV]

Hi Michael,

Can you please share your configuration files and the layout files with me?

Regards,

Bragadeesh

[mibrc_3372801]

Here is my project settings. I cannot share the design files as they are confidential.

[Vison_Zhang]

What object do you put on the proximity sensor, is it direct contact a distance?  Is there a significant temperature difference between the object and the proximity sensor?