PCIe and You: From Everyday Tech to Efficient System Design

As someone who helps engineers tackle PCIe Signal Integrity (SI) challenges, I want to learn how the PCIe Standard impacts our everyday lives. It turns out the PCIe Standard is all around us. In this post, I want to explore how PCIe affects our everyday lives, what it is, and how it can be simulated using software like Keysight EDA Advanced Design System (ADS).

By the end of the post, you will be able to answer three questions:

1. Where is the PCIe standard in your everyday life?
2. What is the PCIe standard?
3. How do you simulate your PCIe system with ADS?

PCIe Standard in Your Everyday Life

Think about your desktop computer in Fig. 1, whether at home or in the office. When you watch a video, browse the internet, or read a blog post on LinkedIn ??, the PCIe standard is hard at work, ensuring that the components inside your machine communicate efficiently.

The PCIe standard serves as a bridge between these components and the motherboard. Graphics cards, sound cards, and even network cards use PCIe protocol to communicate with the CPU. The next time you upgrade your GPU or storage drive, you are benefiting from this high-speed, reliable connection that powers modern computing.

PCIe Standard At-a-glance

Use the graphics card in Fig. 2 as an example, we see that the PCIe standard is a point-to-point serial interconnect system that allows fast communication between devices. The CPU, also known as the root complex, communicates directly with PCIe endpoints, such as your graphics card. This direct connection enables smooth rendering for gaming, streaming, and even running generative AI algorithms.

One of PCIe's biggest advantages is its scalability. You may have noticed the varying sizes of PCIe slots on your motherboard, see Fig. 3. These correspond to different lanes, which allow for different total data throughput depending on the needs of your components.

PCIe Data Throughput

As the transmitter transfers the information bits, PCIe tags on additional bits to help the robustness of the information recovery on the receiver side.

I call the throughput the information rate, the rate at which useful bits are transferred. Fig. 4 shows how a PCIe Gen 1 that runs at 2.5 GT/s has a corresponding throughput of 0.25 GB/s.

In every 10 bits of transferred bits, only 8 are useful data. That means that in every second, only 80% of the 2.5 gigabits are useful. The information (useful bits) received is then 2 gigabits per second. Converting bits to Byte by dividing by 8, we arrive at the throughput 0.25 GB/s.

System Designer for PCIe in ADS

Designing and simulating PCIe systems can be complex, but fortunately, ADS now includes the System Designer for PCIe. With this feature, engineers can model and simulate their entire PCIe system, from the CPU to endpoints like graphics cards, storage, or network cards.

The System Designer for PCIe in ADS allows you to analyze signal integrity, manage your margins, and ensure that your PCIe system meets the high-speed compliance demanded by today’s technology. Whether you are developing cutting-edge hardware or troubleshooting an existing design, ADS provides the tools to make the process more efficient.

Conclusion

You may not have realized it, but PCIe is all around us, powering the technology we use daily. If you're a PCIe designer, thank you for improving our lives with your innovations. And if you're looking for a way to make your design process easier, give System Designer for PCIe in ADS a try. It’s a tool that can simplify your workflow and improve your designs.

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