Effective USB 3.1 filtering and protection

ANP007

The USB connector and standard are one of the most widely implemented and successful interfaces ever used. The applications are commercial and industrial, and both have been pushing the standard to be faster. The USB standard has been updated to version 3.1. This standard increases data transfer speeds to 5 GBits/s (Gen 1) and 10 GBit/s (Gen 2). Higher data transfer speeds are required due to the ever-increasing resolution of media and network data rate requirements.

Increasing the data transfer speed means important parameters need to be considered, as this has implications in data transmission lines. Attenuating unwanted signals while maintaining the speed and integrity of data transfer is of paramount importance for EMI compatibility. For high-speed data lines, Würth Elektronik has common mode chokes for EMI suppression and TVS diodes for ESD protection. The WE-CNSW HF has been developed to attenuate common mode noise signals while maintaining signal integrity up to 10 GBit/s. For ESD protection, the WE-TVS is available with very low capacitances (< 0.6 pF) and is the ideal choice for higher frequencies. These components are also well suited for other high data transfer interfaces such as HDMI 4K, DisplayPort or GBit LAN.

This Application Note outlines the components needed to protect USB 3.1 devices and attenuate EMI that may cause the device to fail EMC testing. This will be demonstrated in USB Type-C dongle to characterize the effectiveness of the components.

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