Undocumented connection on U16-sliceKIT

[Dmil]

Hi,


There are undocumented connections between MPU (U2) N2 (NC), P6 (GND), C39, C27, R46, pin 2 U10 on U16-sliceKIT PCB.
See XM-004146-DF-3-U16_sliceKIT_Core_Board_Schematic.pdf and XS1-U16A-128-FB217-Datasheet(1.9).pdf

See attached picture for illustration.

How these pins must be connected?

[infiniteimprobability]

If you look at the latest version of the schematic you'll see R46 is a zero ohm link that connects GND and AGND. C39 and C27 are AVCSS decouplers - one at the LDO and the other by the chip. This is all correct..

Looking more deeply though, you have exposed an out of date datasheet - we recently made some improvements to the U16 package substrate to reduce ADC noise. Basically AVREF and AVDSS are now internally connected together and come out on N2 and P6. It used to be the case that these were all connected to digital ground internally, however newer substrates separate them.

So using the old datasheet will not let out any magic smoke or cause any functional issue, however following the slicekit schematic may give you better ADC performance. So go with what you see in the slicekit schematic.

Thanks for reporting - good spot. We'll update the datasheets.