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T1022 SerDes Recommended Input Voltage

Question asked by Bob Russell on May 26, 2020
Latest reply on Jun 2, 2020 by Bulat Karymov

Hi,

We are looking to drive a SFP directly from a SerDes output on the T1022. But there is some confusion on what the recommended signals levels for this interface is.

The T1022 has a max VRX-DIFFp-p of 1.6V in 1000Base-KX mode (table 44) my understanding is that will equate to an allowable 0.8V single ended voltage swing on a SerDes input?

 

The SFP MSA states that a SFP can output a signal that is 2V differential (1v singled ended). This exceeds the max of the T1022, but note 1 on table 44 refers to table 3 for recommended operating conditions. Table 3 states SerDes inputs have a recommend range of GND to S1VDD this suggests that the SFP would be ok?

 

Would this also apply when operating in SGMII mode (table 39)?

 

Thanks,

Bob

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