System Analysis Knowledge Bytes - Optimizing LPDDR5X Performance with Sigrity X

30 Apr 2025 • 5 minute read

The System Analysis Knowledge Bytes blog series explores the capabilities and potential of the System Analysis tools offered by Cadence®. In addition to providing insight into the useful features and enhancements in this area, this series aims to broadcast the views of different bloggers and experts, who share their knowledge and experience on all things related to System Analysis.

Low-Power Double Data Rate (LPDDR) memory is a crucial component in modern semiconductor devices, particularly in mobile, IoT, and automotive applications. The latest generation of LPDDR, LPDDR5X, offers higher data rates, improved power efficiency, and reduced latency. Ensuring signal integrity and compliance with JEDEC standards is crucial for designing and verifying LPDDR5X systems. To ensure reliable and high-performance LPDDR5X system design, Cadence's Sigrity X Advanced SI provides a comprehensive environment for modeling, simulating, and analyzing signal-integrity performance. To perform LPDDR5X signoff simulations, users must have an advanced SI license.

Sigrity X Advanced SI technology offers leading-edge signal integrity analysis for PCB and IC packaging designs, covering DC to over 56GHz with advanced features like automated die-to-die SI analysis, topology exploration, and simulation for high-speed interfaces. Supporting IBIS-AMI models and customizable compliance kits, it ensures your designs meet rigorous standards while leveraging frequency domain, time domain, and statistical analysis methods.

In this blog post, we will explore how to use Cadence Sigrity X Advanced SI to perform bus simulation and analysis on an LPDDR5X design topology. We'll cover the essential differences between LPDDR5 and LPDDR5X, clocking mechanisms, and the key components of the LPDDR5X system simulation.

Overview of LPDDR5X

The LPDDR5X standard, published by the Joint Electron Device Engineering Council (JEDEC) in June 2021, represents a specialized category of synchronous LPDDRx devices. LPDDR5X is a type of low-power DDR memory that offers higher data rates, improved power efficiency, and lower latency compared to LPDDR5. LPDDR5X supports data rates of up to 8533 Mega Transfers per second (MTps) and is designed for applications requiring high bandwidth, deterministic low latency, and low power consumption.

LPDDR5 Vs LPDDR5X

LPDDR5 and LPDDR5X are two types of low-power double data rate memories that play a critical role in modern computing systems. The key differences between them are:

Data rates: LPDDR5 offers data rates up to 6400 Mbps, while LPDDR5X offers higher data rates up to 8533 Mbps or more.
Power efficiency: LPDDR5X further enhances power efficiency by incorporating additional features and optimizations, such as lower I/O voltage levels and improved clocking mechanisms.
Latency: LPDDR5X offers reduced latency compared to LPDDR5, with a shorter clock period (tCK) and reduced CAS latency (tCL), row-to-column delay (tRCD), row precharge time (tRP), and write-recovery time (tWR) values.

Clocking in LPDDR5X

LPDDR5X introduces different write-timing and read-timing references. It uses write clock (WCK) for write cycles and read data strobe (RDQS) for read cycles. The system clock (CK) is used to synchronize the operations of the memory controller and the DRAM. The clock divider divides the system clock to generate the write clock and other necessary clock signals. LPDDR5X supports different clock ratios to balance performance and power consumption.

Designing and Simulating LPDDR5X System with Topology Workbench

To perform bus simulation and analysis on a LPDDR5X design topology using Sigrity X Advanced SI, follow these steps:

1. Launch Topology Workbench and load the LPDDR5X design topology.

2. Set up the analysis options, including the type of simulation, corners, I/O models, stimulus pattern, and other settings.

3. Define the timing budget, including the minimum setup and hold times for the transmitter and receiver.

4. Run the bus simulation and generate waveform results, including 2D curves, Eye diagrams, bathtub and BER plots.

5. Analyze the results and generate reports to ensure compatibility with JEDEC standards.

You can also perform a full bus simulation in a single run by enabling all data signals and selecting the Data Write, Data Read, AddCmd, and Ctrl modes. This allows you to generate reports for different signal groups and validate the LPDDR5X design.

Conclusion

LPDDR5X is a critical component in modern computing systems, and designing and simulating reliable and high-performance LPDDR5X systems is essential. Cadence's Sigrity X Advanced SI provides a comprehensive environment for modeling, simulating, and analyzing signal-integrity performance. By following the steps outlined in this blog post, designers can ensure reliable and high-performance LPDDR5X system design and generate reports to ensure compatibility with JEDEC standards.

Click here to learn more about LPDDR5X system simulation using Sigrity Topology Workbench.

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