ZHCSME1C August 2018 – June 2021 DS250DF230
PRODUCTION DATA
For this design example, the following guidelines outlined in Table 9-2 and Table 9-3 apply.
| DESIGN PARAMETER | REQUIREMENT |
|---|---|
| Device placement | Place the DS250DF230s on the receive side of the paddle card such that it is receiving data from the cable, and transmitting towards the host. |
| AC-coupling capacitors | 100-nF, AC-coupling capacitors are required for the RX inputs and the TX outputs. |
| Cable insertion loss | The raw cable insertion loss including the insertion loss of the paddle card must be ≤ 27 dB at 25.78125-Gbps Nyquist frequency (12.9 GHz). This is to ensure that the total loss at the input to the DS250DF230 is ≤ 35 dB at 12.9 GHz. Assuming a worst-case host-side PCB loss of 7 dB, plus a connector loss of 1 dB, the remaining loss allocated for the raw cable and paddle cards is 27 dB. |
| DESIGN PARAMETER | REQUIREMENT |
|---|---|
| Device placement | A full-active QSFP cable will uses 4 pieces of DS250DF230 per paddle card. Typically, two devices will be placed on each side of the paddle card. |
| AC-coupling capacitors | Transmit-side Retimer: 100-nF, AC coupling capacitors are required for the RX inputs and are not required for the TX outputs. This link segment will be AC coupled on the paddle card at the opposite end of the cable. Receive-side Retimer: 100-nF, AC-coupling capacitors are required for the RX inputs and the TX outputs. |
| Cable insertion loss | The raw cable insertion loss including the insertion loss of the paddle card must be ≤ 35 dB at 25.78125-Gbps Nyquist frequency (12.9 GHz). |