Balunless measurement of mixed-mode scattering parameters

Significance of sdd21 in HF technology

ANP004

Increasing data volumes, as well as enormous increases in transfer speeds, place high demands on the signal quality. This is especially evident with the current interface USB 3.0, which is also known as SuperSpeed because of its transfer speed of 5 Gbps. While a common mode inductor was adequate for the previous version USB 2.0 with 480 Mbps to guarantee signal quality, special HF components are now needed for noise suppression. How these differ is shown by the Sdd21 measurement.

Summary

With the sdd21 measurement it could be shown that the HF variants in the WE-CNSW current-compensated data line filter series are suitable for common mode rejection at transmission frequencies up to 6.5 GHz without them affecting differential data signals. Conventional current-compensated filters cannot fulfill this requirement, as demonstrated by the measurement results. The signal quality in communication via the USB 3.0 interface is guaranteed only with special high-frequency components.

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