Intermittent reset of 16C6440 - possible noise issue

[Christopher4187]

I'm at a loss here. I have a 16C6440 that resets sporadically on *most* of the equipment it is installed on. It's a noisy environment but seems like the filter is doing somewhat of a good job keeping the noise at a lower level. I've attached two pics - one of the schematic for the filter and one of the measurements taken between VSS and VDD. The peak-to-peak ripple is approximately 180 mV and the frequency is approximately 233 kHz. When using a DMM, the voltage is steady at 5.223 VDC.

I don't think the ripple voltage is a problem but what about the frequency?