PCB Design Guidelines (HSSI, EMIF, MIPI, True Differential, PDN) User Guide: Agilex™ 5 FPGAs and SoCs

ID 821801
Date 8/29/2025
Public
Document Table of Contents

4.7.5.2. DP and HDMI Connectors

The carrier board utilizes a DP connector that supports DP2.1 up to 20 Gbps and uses a DP re-driver. The total routing length measures 7.2 inches, and the SoM and carrier board exhibit an inter-lane skew of ±250 mil. Altera recommends using differential traces for DP signal routing and to create a cut-out beneath the pin to minimize return loss. To reduce return loss, the carrier board should feature cut-out sizes of 18.96 mil × 53.14 mil on Layer 2. You may optimize sizes by 3D simulation based on specific stack-up or get connector's suggestion. Additionally, remove the solder mask over the top of the connector pad to match the opening window with the connector pad size and incorporate ground vias.

Figure 43. Cut-Out Size on Layer 2 of Carrier Board
Figure 44. Ground Vias on the Carrier Board

The carrier board uses an HDMI connector that supports HDMI 2.1 up to 12 Gbps. The carrier board employs an HDMI re-driver, features a total routing length of 13 mm, and maintains an inter-lane skew of ±200 mil on both SoM and carrier board. The following figure presents the cut-out size on the carrier board for reference. The design adds ground vias and places a cut-out size identical to the signal pad on the Layer 2. Additionally, the manufacturing process removes the solder mask on top of the connector pad.

Figure 45. Cut-Out Size on Layer 2 of Carrier Board
Figure 46. Ground Vias on the Carrier Board