PCB High-Speed Signal Design Guidelines: Agilex™ 5 FPGAs and SoCs

ID 821801
Date 11/18/2024
Public
Document Table of Contents

3.7.3. FMC+ Connectors

The FMC+ connector on the carrier board extends the applications for FPGA. Altera recommends to conduct a 3D simulation to optimize the breakout area based on specific stack-up. The following figure shows the cut-out size of L3 fan-out of FMC+ connector on the carrier board for simulation reference. Aim to reduce the return loss to lower than -15 dB at the Nyquist frequency (achieving lower than -20 dB is preferable) and keep the impedance variation of the cut-out area as minimal as possible (ideally within ±5 ohm). You may use similar cut-out shape and change the size of cut-out shape in your simulation structure based on your own stack-up to optimize the performance.

Figure 47. FMC+ Connector Cut-out Size for L3 Fan-out