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DS280DF810: hw design

hanjun Kim
Prodigy 90 points
Part Number: DS280DF810

I have a question about HW design guides of DS280DF810.

1) When using 25Gbps 6port (2port non-connection), what is the total power consumption?

2) What should I do with connection processing for RXP / RXN pin that is not connected?

I look forward to your prompt reply.

Thank you.

  • +1
    TI__Mastermind 19135 points
    1. You may calculate the max power consumption for thermal analysis using the active power per channel and static power consumption max values from the product datasheet
      • Max total power consumption = (number of active channels)*Wchannel + Wstatic_total = 6*305mW + 1050mW = 2.88W
    2. Unused high speed I/) pins may be left floating or tied to ground. The channel registers routine below may be applied to disable unused retimer channels

    Thanks,

    Rodrigo Natal

  • 0 in reply to Rodrigo Natal
    Prodigy 90 points

    I am going to use 6 retimers for the board currently development.
    If it is 2.88W per part, total power is 17.28W when 6 parts are used under the same conditions.
    Power must be supplied using a switch device rather than an LDO due to its capacity.
    can I use the Voltage regulator(TPS543C20RVFR), which is a switch device, for the power of the retimer?

    i understand that there is no power constraint in the datasheet, is that correct?

  • 0 in reply to hanjun Kim
    TI__Mastermind 19135 points

    Hi,

    For determining the max power consumption for voltage regulator selection the following calculation applies

    • Max total power consumption = (number of active channels)*Wchannel_CDR_locking + Wstatic_total = 6*430mW + 1050mW = 3.63W. This comes out to 1.45A per retimer assuming VDD=2.5V or 8.7A for six retimers
    • Related to TPS543C20RVFR
      • This regulator has max current of 40A, so it has more that sufficient capability to supply current to 6 retimers
      • Per the datasheet "Frequency - Switching 300kHz ~ 2MHz". For this range TI recommends that supply noise amplitude be within 20mVpp. As long as you can be around that target then I would not expect an issue

    Thanks,

    Rodrigo