External Memory Interface Handbook Volume 2: Design Guidelines: For UniPHY-based Device Families

ID 683385
Date 3/06/2023
Document Table of Contents
Give Feedback Input to the FPGA from the LPDDR2 SDRAM Component

The LPDDR2 SDRAM component drives the following input signals into the FPGA:
  • read data
  • DQS

LPDDR2 SDRAM provides the flexibility to adjust drive strength to match the impedance of the memory bus, eliminating the need for termination voltage (VTT) and series termination resistors.

The programmable drive strength options are 34.3 ohms, 40 ohms (default), 48 ohms, 60 ohms, 80 ohms, and 120 ohms. You must perform board simulation to determine the best option for your board layout.

Note: By default, LPDDR2 SDRAM UniPHY IP uses 40 ohm drive strength.