[FAQ] TUSB211A: How does a USB2 redriver boost the signal that passes through it?

Because of the lack of need to break this trace, it may be unclear as to how exactly our USB2 redrivers can be used to compensate for loss in a system. While the means can not be discussed in extensive detail due to patent-protected IP, some information can be given to help construct a general idea. For our USB2 redrivers, the DP/DM pins are connected directly to the USB2 data lane traces with the correct polarity, with the need to send the trace through the redriver or have the trace continue under the redriver being dependent on which redriver is being used.

When powered, the redriver will monitor the DP/DM lanes and wait to see a high-speed handshake to begin boosting the signal. Once it sees this handshake, the redriver enables, boosting the signal by injecting current into the signal as it passes through the DP/DM pins of the redriver. This current injection is aimed towards the rising and falling edges of the signal, supporting the rising and falling edges of the eye in an eye diagram to improve the margin around the edges of the mask in an eye diagram, as well as improving the levels of Vhigh and Vlow in a signal, giving the signal a larger vertical margin that can be needed at longer distances due to insertion loss present in a cable or trace.