long length signal wire on-chip risky?
I am doing layout for a >10Gbps signal. but due to practical issue the signal wire is very long in the layout (>1mm as the red arrow indicates in the uploaded picture)
Is that risky? I think it has to be treated as a transmission line now? But it seems impossible to add extra termination resistors.
Any comments?
Thanks!
Even for less Gbps the PCB trace should be treated as a transmission line.
Anyway, I think your design it will work, but you have to simulate somehow the "Eye Test" performances.
Here you can find some plots regarding performance vs trace length at 10Gbs:
https://www.smtnet.com/library/files...ack-Design.pdf
Yes, it is risky. The very minimum is to extract the equivalent series L and shunt C and see what this does to your circuit performance. Extracting it as a transmission line (equivalent: distributed LC for lossless lines, RLGC for lossy lines) is more accurate to higher frequencies.
I don't know how to extract as distributed RLGC, i think Calibre only extracts as a lumped RLC.
I will try to do extract simulation and see the eye diagram.
That's correct. For more accurate modelling of critical interconnects, full wave EM solvers like Sonnet or ADS Momentum are required.
Yes, it's a good starting point.