Many people ask me about how to pass the FCCID. In fact, the process is not that complex.
That is benefit to there are many module companies’ productions are using RT5350 in ShenZhen, and the foundry I choose has such production already(they also many good software, I am free to use). So I just send VoCore sample to the laboratory, and leave the foundry engineer’s phone number to the laboratory, they did rest for me, that saved me a lot of time.
PS: before the sample send to Lab, the beta version has already tested in factory, all results look good, so my confidence is from there.
About the sample, first of all, the board must in good quality. I am not sure what test they will do, but if the quality is not good, it might broken in half way. My samples are made by machine, better than my hand make ones.
About the test process, I knows little about that, I only know if the EMC can not pass, the laboratory will ask you if you want to add a metal shell, then do the test again(of course, your FCCID production photo will show the shell too, and your final production must have that metal shell)
VoCore passed FCCID in one time without any shell, that should thanks to the simulation software, when I design it, I set its simulation parameters to 1GHz, 3.3V to all traces, the sim result max crosstalk voltage is under 60mV, it should be a good result due to other board such as RM04 the crosstalk value greater than 300mV, its 30% traces even more than 800mV, maybe such reason they have to have a shell. The software I used name is HyperLync.
To lower the crosstalk voltage, we must keep trace distance 3W at least. And the trace should as short as possible.
Autumn comes, my house temperature is 25C, and test on new VoCore with dock several hours, the max temperature on the surface is lower than 50C, very good not hot anymore, just a little warm.