SLVSD02E March 2015 – August 2021 TPS65982
The USB-PD driver meets the defined USB-PD BMC TX masks. Since a BMC coded 1 contains a signal edge at the beginning and middle of the UI, and the BMC coded 0 contains only an edge at the beginning, the masks are different for each. The USB-PD receiver meets the defined USB-PD BMC Rx masks. The boundaries of the Rx outer mask are specified to accommodate a change in signal amplitude because of the ground offset through the cable. The Rx masks are therefore larger than the boundaries of the TX outer mask. Similarly, the boundaries of the Rx inner mask are smaller than the boundaries of the TX inner mask. Triangular time masks are superimposed on the TX outer masks and defined at the signal transitions to require a minimum edge rate that will have minimal impact on adjacent higher speed lanes. The TX inner mask enforces the maximum limits on the rise and fall times. Refer to the USB-PD Specifications for more details.