A high-speed PCI-compliant connector for all industries
PCIe – An Interface with a Bright Future
Technological Advancements, Design Challenges, and Solutions for Embedded Systems.
PCI, or Peripheral Component Interconnect, is a bus protocol for chip-to-chip communication and the connection of external peripheral devices.
Since the introduction of the PCI standard in the early 1990s, data communication in computer systems has undergone a fundamental transformation. Today, PCI provides a highly scalable and powerful interface that is used in virtually all areas of modern electronics—from high-end graphics cards to servers and embedded systems. However, as performance increases, so do the demands on printed circuit boards, signal quality, and electromagnetic compatibility. The following article highlights the technological advancements of PCI, the associated challenges in PCB design, and presents potential solutions using board-to-board connector systems for future high-speed applications.
PCI, or Peripheral Component Interconnect, is a bus protocol for chip-to-chip communication and the connection of external peripheral devices.
Since the introduction of the PCI standard in the early 1990s, data communication in computer systems has undergone a fundamental transformation. Today, PCI provides a highly scalable and powerful interface that is used in virtually all areas of modern electronics—from high-end graphics cards to servers and embedded systems. However, as performance increases, so do the demands on printed circuit boards, signal quality, and electromagnetic compatibility. The following article highlights the technological advancements of PCI, the associated challenges in PCB design, and presents potential solutions using board-to-board connector systems for future high-speed applications.
The Evolution from PCI to PCIe
The transition from traditional PCI to PCI Express (PCIe) around 2004 marked the beginning of a new era in data transmission. While PCI 2.2 was relatively limited at a maximum of 133 MB/s, PCIe 6.0 in the (x8) configuration theoretically allows for up to 64 GB/s—an increase of nearly a thousandfold. Notably, the innovation cycle maintains a cadence of approximately three years, during which the high-speed bandwidth of PCIe protocols doubles.
This tremendous advancement is particularly evident in data-intensive application areas such as artificial intelligence, autonomous driving, and high-performance computing. While PCIe 5.0 systems in data centers already support 32 GB/s, the traditional embedded market currently relies mainly on PCIe 3.0 applications with 8 GB/s. The first PCIe 4.0 modules are just being introduced, but a broader market rollout is not expected for about five years. PCIe 4.0 protocols are currently used for control systems for semi-automated driving in accordance with SEA Level 3; for fully automated driving in accordance with Levels 4 and 5, the PCIe 5.0 system is required.
Why is PCIe ahead of its time?
It is striking that the development of PCIe interfaces often progresses much faster than their actual use. There are several reasons for this:
- Future-proofing: Manufacturers design interfaces with future requirements in mind—they are intended to still offer sufficient performance headroom years down the line.
- Technological innovations: Advances in materials and manufacturing techniques enable ever-higher data rates.
- Scalability: PCIe is modular and can be flexibly adapted to future requirements.
- Market pressure: Manufacturers are competing with one another and always want to offer the latest technology—even if it is not yet being fully utilized.
PCIe technology is being applied across a wide range of applications, from server-based artificial intelligence and autonomous driving to embedded systems in industrial automation.
Challenges in the Design of Modern PCIe Systems
The ever-increasing volume of data presents developers with numerous challenges. Many new applications are required to process twice as much data while occupying the same amount of space as older versions. Sooner or later, this inevitably leads to increasingly complex designs and, in some cases, to the miniaturization of individual components, which in turn drives up prices.
Expensive PCB design
As data rates increase, so do the demands on physical signal routing. High-frequency signals exceeding 16 Gbit/s (e.g., in PCIe 4.0) require complex PCB designs with multiple layers, specialized materials, and precisely controlled impedance. Microvias, specialized dielectrics, and high-density interconnects (HDI) further drive up manufacturing costs.
Limitations of 25 Gbps Ethernet on COM Express
Despite the ample bandwidth provided by PCIe 4.0 (16 Gbps per lane), the implementation of 25 Gbps Ethernet on COM-Express (Computer on Module) has not yet been fully realized. Main reasons:
- Lack of integration of 25 Gbps Ethernet controllers in COM modules
- Inadequate driver and firmware support
- Limited signal quality due to existing components
- Incompatible cable and connector systems
Space requirements on the circuit board for 440 signals
Another bottleneck is the physical space available on the printed circuit board. Applications with up to 400 signals—such as FPGAs or COM Express modules—require complex multilayer routing (often 10–16 layers), controlled impedance, differential pairs, and an EMC-optimized layout. The miniaturization of such systems further exacerbates this problem.
Electromagnetic Compatibility (EMC)
Higher frequencies result in stronger electromagnetic emissions. In highly integrated designs with tight signal spacing, reflections, crosstalk, and interference occur—which requires robust shielding concepts and ground paths.
High-speed connectors for optimal data transmission
The challenges described—ranging from costly PCB design and space constraints due to high signal density to EMC issues—make it clear that traditional design approaches are increasingly reaching their limits in modern PCIe applications. In the embedded sector in particular, there is a need for innovative connectivity solutions that enable high data rates reliably, in a space-saving manner, and at an optimized cost.
The new Colibri® interface, available in three variants, is specifically engineered for high-speed applications in the embedded sector:- 10+: For COM Express
modules according to Revision 2.1
- 16+: For COM Express modules according to Revision 3.1
- 25+ For COM Express modules according to Revision 3.1 and 25 Gbit/s Ethernet applications
The limit for a connector in PCIe 4.0 applications is an insertion loss of –1.8 dB at a frequency of 8 GHz.
The Colibri 25+ connector exceeds PCIe requirements, allowing the connector to compensate for losses in the high-speed design of the cost-optimized PCB.
The new Colibri® interface, available in three variants, is specifically engineered for high-speed applications in the embedded sector:- 10+: For COM Express
modules according to Revision 2.1
- 16+: For COM Express modules according to Revision 3.1
- 25+ For COM Express modules according to Revision 3.1 and 25 Gbit/s Ethernet applications
The limit for a connector in PCIe 4.0 applications is an insertion loss of –1.8 dB at a frequency of 8 GHz.
The Colibri 25+ connector exceeds PCIe requirements, allowing the connector to compensate for losses in the high-speed design of the cost-optimized PCB.
The benefits of Colibri:
- More cost-effective PCB design thanks to an optimized layout structure
- Supports 25 Gbit/s Ethernet for the first time on a COM Express basis
- Miniaturization & EMC optimization through integrated shielding
- Future-proof for PCIe 4.0 applications
Colibri thus enables reliable and scalable signal transmission in board-to-board applications, even in tight spaces and at high data rates—making it a key foundation for the next generation of modular embedded systems as well as applications in PCI interfaces.
Conclusion
PCIe technology has become the backbone of modern computer systems and is now widely used across numerous industries. With each new generation, data rates increase—and with them, the challenges for developers and hardware designers. In the embedded sector in particular, there is a growing demand for solutions like Colibri that enable cost-effective, scalable, and future-proof system architectures. The market is evolving rapidly, and with it, the requirements—the technology is ready.
Are you looking for a specific connector?
product list
Do you have any
questions? Please contact us.
Submit a request via the form
+49 8861 2501 0
sales@ept.de
questions? Please contact us.
Submit a request via the form
+49 8861 2501 0
sales@ept.de