I hope I am not doing something wrong by posting in this forum. This is my first visit here, and first post.
I am trying to make sense of a possible discrepancy I have noted that regards the input/buffer channels on the PCM4222EVM. This could be my inexperience or total stupidity of things, but I need to modify the board slightly to include capacitors to avoid possible DC offsets and wanted to be safe rather than sorry.
On page 17 of the PCM4222EVM user guide http://focus.tij.co.jp/jp/lit/ug/sbau124/sbau124.pdf , in the schematic (Fig.4), in the buffer area, C1, C2, C3, C4, all have their positive ends facing the input jacks with their negative ends facing the input of the OPA1632.
In the PCM4222 user guide http://focus.ti.com/lit/ds/symlink/pcm4222.pdf , page 32, alternate buffer guides (Figs. 51 & 52), the protection capacitors on the inputs have their negative ends facing the input connector, and the positive ends facing the inputs to the various chips.
Shouldn't the positive ends be pointed toward the buffer chips/converter inputs, as a way of preventing reverse bias, or am I stupidly missing something here? I don't want to kill my EVM before I have a chance to put it to use!
I sincerely appreciate your time and consideration.
Also, am I the only one having trouble deciphering some of the dip switch settings? If anyone has some experience in this area, could you share an email address so that I might write you directly and avoid further embarrassment?
