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SN75DP130 input differential voltage

Sean Moon
Prodigy 340 points
Other Parts Discussed in Thread: SN75DP130

Dear team,

I've been told that the MINIMUM peak-to-peak input differential voltage in the datasheet (300mV) is VID after the RX equalizer.

Then, what if VID after the equalizer is less than 300mV? 

My customer said the peak-to-peak input differential voltage will be 70mV and data rate is 2.7Gbps (HBR). In the datasheet, the maximum EQ gain at HBR is 9dB.

So VID after the equalizer will be 70mV x 9dB = 70mV x 2.81 = 196.7mV which is less than 300mV. Is my understanding right?

In this situation, is it impossible for DP130 to re-drive the signals? 

Actually, I've asked this question many times but haven't received the clear answer.

Your clear answer will be very appreciated. Thanks.

Best regards,

  • 0
    TI__Mastermind 36085 points

    Hello Sean,

    In a first instance and according to the DS, the input differential voltage must be >300mV it doesn't say anything about after equalization. Therefore the input voltage you mentioned is quite lower than the minimum acceptable by the SN75DP130.

    Let me confirm with my team about the VID post equalization, however taking into account this added margin by the EQ, your calculations are right and the SN75DP130 still wouldn't be able to handle such small input signal.

    Best regards,
    Diego

  • 0 in reply to Diego Cortes
    TI__Prodigy 340 points
    Hi Diego,

    I've asked the same questions to a system engineer. At first, I was asking about DP120 with that low level signal and he said we would have to use DP130 because the input signal level is too low and DP130 has the best equalizers. Also, he said the input differential voltage in the datasheet looks at after the equalizer. I'm still very confused. It's very urgent and I really need this information as soon as possible.

    Best regards,
  • 0 in reply to Sean Moon
    TI__Mastermind 36085 points
    Hello,

    This thread is being handled offline.

    Regards,
    Diego.