Abstract:
Methods and apparatus for equalization of a high speed serial bus. Various aspects of the present disclosure are directed to a well-tuned passive equalization circuit for use with high frequency differential signals that suffer from e.g., impedance mismatches, impedance discontinuities (e.g., connectors, etc.). In one embodiment, a shunting circuit is inserted between the differential terminals of a Universal Serial Bus (USB) cable, connector, etc. The shunting circuit is configured to “open” at low frequencies to enable Full Speed (FS) enumeration, while also providing sufficiently high impedance at high frequencies to enable High Speed (HS) operation. In one such implementation, the shunting circuit includes a tuned resistor, capacitor, inductor, and switch element arranged in series.