Hello board, I want to route a signal between 2 adjacent boards(track length is about 6 inch), output of board A will be input of board B. I deally I do not want to have difference between level of these two signals more than 10uV in two different boards. though I have used star configuration of GND and thick GND tracks(60 mil) for each board but GND tracks to system reference GND is long (about 10 inch each) and though there are not much current(less than 30 mA at worst conditions) but a simple calculation shows that even 350 uOhm of resistance is enough to cause more than 10uV bounce. To make problem even more complex, because these two boards are within a complex feedback system I'm very reluctant to use instrument diff-amps because of unwanted phase shift and oscillation. First is there any trick so I can route this signal, single ended and also retaining precision that I mentioned?
If not I thought maybe I can route them differentially but instead of using an opamp I use two 10k precision resistors in series between Signal and GND of board A and get half of the signal from junction point of these two resistors (in board B).
I'll be gratefull for any practical suggestion, thanks a lot