| 摘要 |
Switching and repeating applications using an impedance matched source follower improve performance of high speed links such as PCI Express, HDMI, DisplayPort and DVI by reducing attenuation and other degradation of high speed signals, including those with transmit pre-emphasis, by avoiding impedance discontinuities over process, voltage and temperature variations and by driving a broader range of loads, e.g., heavily capacitive loads. A circuit for switching or repeating signals on a single-ended or differential high speed link may comprise a source follower with input and output impedances matched to input and output transmission lines on the high speed link. The source follower is biased by a constant transconductance circuit, an external calibration circuit or other circuit to provide an essentially constant output impedance over process, voltage and temperature variations.
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