DS25MB200,pdf datasheet (Dual

The DS25MB200 is a dual signal conditioning 2:1 multiplexer
and 1:2 fan-out buffer designed for use in backplane redundancy
applications. Signal conditioning features include input
equalization and programmable output pre-emphasis that enable
data communication in FR4 backplanes up to 2.5 Gbps.
Each input stage has a fixed equalizer to reduce ISI distortion
from board traces. All output drivers have 4 selectable steps
of pre-emphasis to compensate for transmission losses from
long FR4 backplanes and reduce deterministic jitter. The preemphasis
levels can be independently controlled for the lineside
and switch-side drivers. The internal loopback paths from
switch-side input to switch-side output enable at-speed system
testing. All receiver inputs are internally terminated with
100Ω differential terminating resistors. All drivers are internally
terminated with 50Ω to VCC.