topic Re: iMX8M Plus PCIe TX/RX Impedance in i.MX Processors

iMX8M Plus PCIe TX/RX Impedance

danny_ayers — Wed, 13 Aug 2025 19:44:09 GMT

I am interfacing the iMX8Mplus directly (via pcb trace and AC coupling capacitors, no connectors) to a gen 2 PCIe device which specifies 100 ohm differential impedance for its TX and RX pairs. The connection path is < 2 inches.

Can the iMX8 tolerate 100 ohms routing in these conditions, or if not, how to handle this situation?

Thank You,

Danny

Re: iMX8M Plus PCIe TX/RX Impedance

joanxie — Thu, 14 Aug 2025 07:30:57 GMT

based on IMX8MP HDG, we suggest customer to use 85ohm, 85ohm has more reliable than 100ohm when use the larger inches in length, since customer only 2inches, 100ohm can be acceptable, if customer doesn't have any compliance issue, they can use this, but I will double confirm this from HW team again, if get further information, I will let you know it

Re: iMX8M Plus PCIe TX/RX Impedance

danny_ayers — Thu, 14 Aug 2025 14:24:56 GMT

Thank You very much for that reply. Please advise with your hardware team's agreement.

Re: iMX8M Plus PCIe TX/RX Impedance

joanxie — Fri, 15 Aug 2025 09:46:39 GMT

confirmed that it's fine as I mentioned before