External Memory Interfaces Agilex™ 7 M-Series FPGA IP User Guide

ID 772538
Date 11/18/2024
Public
Document Table of Contents

8.5.7.3. Example of an LPDDR5 Layout on an Altera® FPGA Platform Board

The following figures show the layout example of a single rank LPDDR5 x 32-bit device with a pitch size of 0.7×0.8mm on an Altera FPGA platform design.

The LPDDR5 signal routing is on upper layers to avoid vertical crosstalk on interface and achieve high performance.

Figure 58. Board Layout and Via Pattern for Single Rank LPDDR5 x32 device on an Altera FPGA Platform Design

In addition, the following figure shows a LPDDR5 64-bit device board routing sample with pitch dimension of 0.4×0.4mm. The microvia has been used for via transitions on this interface. The microvia mentioned in the following is from top layer to layer 3, it belongs to Type-III stack-up for easier fan-out, not the same as microvia used in Type-IV stack-up. Only one lamination cycle is required, therefore the cost is not increased as much as microvias in Type-IV. You can also use normal PTH with backdrilling to fan out.

Figure 59. Board Via Pattern for LPDDR5 64-bit Device