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

ID 683385
Date 3/06/2023
Document Table of Contents

1.1.15. LPDDR2 Data, Data Strobe, and DM Signals

LPDDR2 devices use bidirectional and differential data strobes.

Differential DQS operation enables improved system timing due to reduced crosstalk and less simultaneous switching noise on the strobe output drivers. The DQ pins are also bidirectional. DQS is edge-aligned with the read data and centered with the write data.

DM is the input mask for the write data signal. Input data is masked when DM is sampled high coincident with that input data during a write access.