ADS7953: EMI throws off reference?

Part Number: ADS7953


I have an ADS7953 in my design, and I had a failure during EMC testing in the EMI chamber during what appears to be BCI at 1MHz.  The chip fails in such that all of the channels work for say 50% of the range (almost like there is an offset).  So it seems the reference voltage is being messed up?  What is causing this?

Some things to note:  the REF5025 is putting out a solid 2.5V, the layout is done as is shown in the data sheet, I have 4 unused channels that have the RC filter network on them, however they are floating.

If I replace the chip post failure, everything is fine, so it does seem that something is getting messed up in the chip.

What can I do to improve the robustness of my design to survive BCI?

Thank you!


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