BBT3821 pdf datasheet (Octal 2

The nLiten BBT3821 is a fully integrated octal 2.488Gbps to
3.1875Gbps Clock and Data Recovery (CDR) circuit and
Retimer ideal for high bandwidth serial electrical or optical
communications systems. It extracts timing information and
data from serial inputs at 2.488Gbps to 3.1875Gbps,
covering 10 Gigabit Fiber Channel (10GFC) and IEEE 802.3
specified 10 Gigabit Ethernet eXtended Attachment Unit
Interface (XAUI) rates.
Each BBT3821 accepts two sets of four high-speed
differential serial signals, re-times them with a local
Reference Clock, reduces jitter, and delivers eight clean
high-speed signals. The BBT3821 provides a full-function
XAUI-to-10GBASE-CX4 PMA/PMD (compatible with the
IEEE 802.3ak specification), and also can be configured to
provide the electrical portion of a XAUI-to-10GBASE-LX4
PMA/PMD, needing only laser drivers and photo detectors to
be added. In both these applications, the XAUI side can be
configured to implement the XENPAK MSA_R3.0
specification, including full NVR and DOM support. The
XPAK and X2 specifications currently all reference the
XENPAK specification, and are supported in exactly the
same manner. The BBT3821 can also be used to enhance a
single full-duplex 10 Gigabit XAUI link, extending the driving
distance of the high-speed (2.488Gbps to 3.1875Gbps)
differential traces to 40 inches of FR4 PCB (assuming a
proper impedance-controlled layout).