I'm a new hardware design engineer. I have a few questions about high speed pcb design.
1) when I search high speed pcb design, I saw pcb routing like snake. What is this ?
2) When I draw a high speed way (like can-bus line), I used differential pair. Can ı use with only differential pair at all high speed line ? Or Should I do different things ? Like lenght matching.
3) How many MHZ after a line being high speed line?
1) It's extra parasitic inductance built into a trace.
2) No, there are many way's to create a transmission line.
Source: http://www.gsm-modem.de/M2M/m2m-faq/transmission-line/
3) Roughly 50Mhz, after that transmission line effects start to take hold.
1) to match lengths of wires in the differential pair, and in case of buses with multiple parallel differential pairs, to match the length of all pairs.
2) a little difficult to understand what you are asking. But if some interface is differential then use it. Match lengths but only up to what is necessary and practical - don't aim for 1mm length difference if 10mm is irrelevant.
3) that would depend on context. RS485 is differential but you can transmit at 1 bit/s rate or 10M bit/s rate. Coaxial SPDIF audio can be 12.288 Mbit/s or more but is not differential. Mostly the signal is defined by the slew rate of the edges.
4) most likely yes, but currently I can't suggest a source other than search engines and wikipedia about the subject to find books that match.
