2 When to use a Retimer Versus Redriver

Table 2-1 lists a high-level summary of chip-to-chip interface types based on their transmission channel's insertion loss at around the Nyquist frequency for 25Gbps data rate. The amount of channel loss will dictate the level of signal conditioning required for an error free chip-to-chip link. Some portion of system interconnects will have channel loss that is within the equalization compensation capability of the chips being linked together. Such links do not require signal conditioning. Links requiring a moderate amount of compensation (up to 20dB) may use a redriver instead of a retimer, in that way realizing some relative savings in power consumption and cost. Links involving transmission across a channel with very high loss require the use of a retimer.