[SOLVED] A20-OLinuXino-MICRO-4GB, impedance line, characteristic impedance

[huxyz]

We are working on a project on which we are modifying A20-OLinuXino-MICRO-4GB board. We are in contact with a PCB manufacturer and they are asking whether the PCB design consists of impedance line or not. We didnt make any modification related to connections between A20 and SDRAMs on PCB. Therefore we can use the same technical data as is the case with OLinuXino board. Do you know what the characteristic impedance (50ohm ?? 60ohm) is for the high speed routes on A20-OLinuXino-MICRO-4GB? And if i give this information to the manufacturer, is it sufficient for them to fabricate the boards, or should i give them copper and isolation thickness details of the layers? What kind of information should i give to the manufacturer for this issue ? I would really appreciate if someone shed a light on this impedance stuff.

[LubOlimex]

Which hardware revisions are you looking at? If you are looking at revision G1 (the latest one at GitHub) - then the impedance of the high-speed routes (5 mil width ones) seems to be 60 Ohm +/- 10%.

Either they have to calculate the parameters or you need to know details about their machines and calculate it yourself. In most cases it is the first scenario - the company that manufactures the boards takes care of these details.

Best regards,
Lub/OLIMEX

[huxyz]

Thanks a lot LubOlimex, you have just saved my day