1 Overview of TI 25G/28G Retimers and Redrivers

Figure 1-1 and Figure 1-2 illustrate the functional block diagrams for TI's 25G/28G retimers and redrivers. As evident from the block diagrams, the retimer and redriver have a few key functional differences.

• The retimer implements clock and data recovery (CDR) and sampler functional blocks, thus enabling it to output a retimed version of the input signal with lower jitter. The redriver on the other hand does not incorporate the retiming-CDR related functional blocks.
• The redriver implements a two-stage continuous time linear equalizer (CTLE) as its only form of receive equalization.
• In addition to CTLE, the retimer also implements a decision feedback equalizer (DFE). Thus the retimer is equipped with more enhanced post-cursor equalization function.
• The retimer incorporates additional diagnostic functions not available on the redriver, including PRBS pattern generation and checking and eye monitor functions.

Figure 1-1 DS280DF810 Retimer Functional Block Diagram

Figure 1-2 DS280MB810 Redriver Functional Block Diagram