Greetings Kinetis experts,
I have a quick question. Is there a special reason why USB stick of KW24D512 has single ended impedance of 70 ohm and not 50 ohm for all lines?
Regards,
Mete
Hello Mete,
I mean the instructions provided in the .brd file (see NOTES section).
Where did you get the 8.000 of width?
You can also ask your manufacturer to get the 50 Ohm single ended requirement.
Hi,
Sorry I did not aware the USB impedance changed fr this part. From what I know what we always using is the 1:1 (50/50) which was found to provide the best performance for our FRDM, TWR and USB designs. Please let me know where indicate the impedance changed and I will help to confirm.
Hello Fang,
Thanks for your reply. When the below stack up is used for the board (from the open source .brd file)
Signle ended impedance of 8 mil lines become as follows (you need to zoom in sorry)
Am I missing anything? Different dielectric perhaps?
Regards,
Mete