E-Tile Transceiver PHY User Guide

ID 683723
Date 9/08/2023
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7.2. Dynamic Reconfiguration Maximum Data Rate Switch

If you use multiple transceiver channels in an E-tile, where at least one is configured in PAM4 high data rate (> 30 Gbps), you cannot change the data rate on any other channel on the same tile by greater than 20 Gbps (regardless of whether the channels are NRZ or PAM4) at a time in order to minimize the rate switch's effect on the PAM4 high data rate channel’s link performance. You must step the data rate change, with a minimum step duration of 200 ms.

For example, if you have the following configuration:
  • One PAM4 high data rate channel running at 56 Gbps (channel a)
  • One NRZ channel running at 28 Gbps (channel b)

And you want to change the data rate on the second channel from 28 Gbps to 5 Gbps, you must do it in two steps (first changing the data rate from 28 Gbps to 8 Gbps and then from 8 Gbps to 5 Gbps), with channel b running at 8 Gbps for a minimum of 200 ms. However, if you want to change the data rate on channel b from 28 Gbps to 25 Gbps, there is no restriction since the data rate change delta is less than 20 Gbps.