Refer to the Vivado Device Model section of the Kria K26 SOM Data Sheet (DS987) for the GTH transceiver maximum transfer rate.
- To minimize the impedance discontinuity at the SOM connector interface, route the GTH signals using a 90Ω differential impedance.
- Match P and N differential signals to within ±0.5 mils of each other.
- Route GTH signals in internal routing layers as a stripline structure.
- Route GTH signals with a maximum of two via transitions. Ensure adequate ground return vias are placed next to the signal vias to minimize crosstalk.
- Route GTH signals to have a maximum via stub length of less than 24 mils. It is a good design practice to minimize the stub length to avoid reflections.
- GTH differential signals to all other signal spacing should be five times the distance between the signal to the nearest GND plane.
- For design flexibility, no transceiver capacitors are added to the data lanes on the GTH transceivers.
- For more information on proper decoupling and interface standards, see the PCB Design Checklist chapter in the UltraScale Architecture GTH Transceivers User Guide (UG576).