DS110DF111 / Propagation Delay

Hi Kato-san,

This is difficult to say what the propagation delay is for the entire system, because we do not know the propagation delay before and after the DS125DF111.

In the datasheet, the typical propagation delay for retimed data is:

So, if you are at 10.3125 Gbps, then Tpd (typ) = 200E-12 + 1.5/10.3125E9 = 348.1 ps, just as you calculated.

The retimers add more propagation delay than their redriver counterparts due to a higher level of internal components, including the CDR. However, from bench validation results, the maximum delay should not exceed more than 300 ps + 1.5UI. Therefore, the propagation delay in a 10.3125 Gbps application worst case scenario is <=450 ps.

Note that the DS125DF111 and DS110DF111 primary difference is manifested in a different VCO frequency range. From a Tpd standpoint, they are the same.

Thanks,

Michael

Hi Kato-san,

The minimum propagation delay is approximately 1.5 UI + 150 ps to account for +/- 25% variation across parts. My guess is that it may be slightly higher than this based on variation over temperature and voltage.

Thanks,

Michael