FEA SIMULATION AIDS SIGNAL INTEGRITY IN HIGH-SPEED CONNECTOR DESIGNS CHEN GOLDBERG, GENERAL MANAGER, GREENCONN
The rapid development of high-speed signal software and hardware across all industries has created a higher level of frequency and bandwidth. Accordingly, the overall performance requirements for connector components are also more stringent. At the same time, the miniaturization of device and package forms, interconnects, and other devices within a system present additional design challenges. All these facts have a significant impact on signal transmission integrity. THE BASIC THEORY OF SIGNAL INTEGRITY OF HIGH-SPEED CONNECTORS As the overall structure of most devices and equipment become significantly smaller and operate at higher frequencies, signal integrity issues are arising and require special attention. Characteristic impedance, insertion loss, return loss, and crosstalk — among which impedance and crosstalk have the greatest impact on the signal integrity of a connector — must all be monitored at the testing level to ensure optimal device performance. Scattering parameters (S-parameters) are often used in signal integrity as a standard format to describe the broadband high-frequency behavior of interconnects. S-parameters are a format
for describing how a standard waveform of an interconnect or component scatters away during the DUT (Device Under Test) process.
Standard Waveform Input DUT Scattering. In this graphic, Transmission Waveform S21 represents the insertion loss, while Reflection Waveform S11 represents the return loss.
THE KEY FACTORS AFFECTING THE SIGNAL INTEGRITY OF HIGH-SPEED CONNECTORS Generally, the main factors affecting the signal integrity of high-speed connectors are design space, transmission rate, and signal loss. Different PCB layout designs are closely related to these factors, which have a critical impact on the overall signal integrity. Under different PCB layout designs, the high-frequency characteristics presented by the connector will be affected.
At present, the standard high-speed connector has a complete structure and specification to follow.
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