Signal Integrity

We can support your high speed design before the layout or tackle issues after the layout has been done.

Overview

With today’s high speed designs, signal integrity is getting more and more important for the reliable operation of a system. Cross talk, mismatching, discontinuities in the signal path and dispersion effect the integrity of the design the more the higher the operating frequencies are.

Felicitas Customized Engineering supports in such challenges in all design phases. We can analyze the requirements and make proposals for the placement, the PCB material, the layout and the overall system setup. Or we can carry out some of the design. Or just analyze what is the reason and the cure for a failure.

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Applications

There are many different digital technologies used which requires careful handling of signal integrity, for example:

  • DDRAMs
  • PCI Express
  • Backplanes
  • FPGAs

On the other hand, modern wireless communication standards requires the same amount of care, for example

  • Wi-Fi
  • ZigBee
  • Bluetooth
  • LTE
  • EnOcean

Details

Design Aspects

There are many different aspects to consider in order to design a successful system. Some of them are:

PCB Material

There are high-performance materials available with excellent properties up to 100GHz. But they suffer from high price and are often difficult to process. In many cases a well designed PCB based on a good FR-4 material will do the trick.

Transmission Lines

A simple Microstrip (just a well-defined track above a ground plane) is easy to implement but has a number of drawbacks (loss, dispersion, radiation). Better transmission line variants can be used, but require more real estate or more layers and additional vias which might contradict the advantages.

Vias

Vias present a discontinuity in the transmission line and therefore are always the cause for reflections and signal degradation. We can evaluate the effect of vias in a full-wave simulation with our FieldSover 3D.

Connectors and Sockets

They usually have a huge influence to the design. Not just the type of connector or socket is important, it is also decisive how the signals are routed and how the pads of the connectors are carried out. We can simulate the behavior of the sockets or connectors based on models from the vendors. If those are not available, we can also use our FieldSolver 3D to simulate them based on mechanical data.

Termination and Matching

For digital designs, termination is often not required since it is already integrated in the transmitters. For wireless communication and the use of antennas, the matching can prove difficult. Especially when a wide frequency band or multiple frequency bands are required.