Hi,
I am using the ST25R3916B on a custom PCB and am having some field failures where it seem that the device is failing to respond on SPI to my microcontroller. When I get the board back in house I can see that my first SPI command to read the ID register is not working. Rebooting will sometimes allow me to properly read the ID, but it seems that once the issue starts eventually the chip will get itself into a state where it stops responding altogether. I have scoped out my SPI signals and everything looks good coming out of my uC, but I then get nothing on MISO.
The rest of the board works fine and all power rails look fine so I am a bit confused on what to try next as it seems like the chip is just dying. I currently have about 42 of these boards in the field and have seen ~10% fail with this failure mode and need to be replaced. Another data point - This is the second version of the product. The previous one used a mix of 3911Bs and 3915s and we never saw this issue. Changing to the 3916B was essentially the only change on this revision. Any help is greatly appreciated.
