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SN65LVDS95: Unterminated Inputs and Outputs for Transmitter and Reciever ICs

Paul Shaffer
Prodigy 20 points
Part Number: SN65LVDS95
Other Parts Discussed in Thread: DS90LV049, , SN65LVDS96, DS92LX1622, DS92LX1621, DS92LV16, DS15BR400

For the SN65LVDS95 Transmitter and SN65LVDS96 Receiver, what is the best practice for terminating unused inputs and unused outputs?

I have read through the attached TI application note, but I need more guidance.

How to Terminate LVDS Connections with DC and AC Coupling

For our communication scheme, we are using SSP1X at 350Mb/s and 50MHz clock.

Also, for the replac ement of SN65LVDS95 Tx and SN65LVDS96 Rx, what part do you recommend DS90LV049 or other parts?

  • 0
    TI__Mastermind 31465 points

    Hi Paul,

    If you have unused differential transmitters on the LVDS95 and unused differential receivers on the LVDS96, you do not need to terminate these pins. Termination is only required for differential lines that are in use.

    What are you looking for in a replacement part? The DS90LV049 has different functionality as it is a transceiver and not a serializer or deserializer.

    Best,

    Jack

  • 0 in reply to Jack Scherlag
    Prodigy 20 points

    Hi Jack,  For the replacement part, we are looking at replacing the older LVDS96/95 with another Serial Deserial chip set.  Thank You, Paul

  • 0 in reply to Paul Shaffer
    TI__Mastermind 31465 points

    Hi Paul,

    One more question. What is the SSP1X communication protocol? Is this for transmitting video data or communication between processors? Most of our SERDES parts are made specifically for transmitting video data.

    Best,

    Jack

  • 0 in reply to Jack Scherlag
    Prodigy 20 points

    Hi Jack, yes, the SSP1X is for communication only, no video.  Do you recommend another vendor ICs or what are your recommendations?  Thank You, Paul

  • 0 in reply to Paul Shaffer
    TI__Mastermind 31465 points

    Hi Paul,

    There are a couple of TI options depending on your criteria for a replacement part. How many LVCMOS/TTL inputs do you need to serialize? Do you need communication across the link?

    For example

    • If you want a single lane SERDES and a bi-directional control channel: Use the DS92LX1621/DS92LX1622
    • If you want a want simpler single SERDES: Use the DS92LV16. It can function as both the serializer and deserializer

    Best,

    Jack

  • 0 in reply to Jack Scherlag
    Prodigy 20 points

    Hi Jack,

    We have 3 SSP1X communication channels. For each channel, we have CLOCK, Transmit, and Receive. On each side of the communication channels, we have serial data over the cable, then parallel 7 bits to the FPGAs on each side of the communication channel. We use a Serial-DeSerial IC TI part number SN65LVDS96 and a Redriver IC TI part number DS15BR400TSQ/NOPB for each communication channel.


    Question 1:  Have any ESD failures for the Serial-DeSerial IC TI part number SN65LVDS96?  If yes, what were the failure modes?  Are there any CRC errors during the ESD tests?

    Question 2:  Have any ESD failures ever occurred for the Redriver IC TI part number DS15BR400TSQ/NOPB?  If yes, what were the failure modes? Are there any CRC errors during the ESD tests?

  • 0 in reply to Paul Shaffer
    TI__Mastermind 31465 points

    Hi Paul,

    Paul Shaffer said:
    Question 1:  Have any ESD failures for the Serial-DeSerial IC TI part number SN65LVDS96?  If yes, what were the failure modes?  Are there any CRC errors during the ESD tests?

    ESD events that are below the listed ESD limits will result in any signal being shorted to ground. The "Equivalent Input and Output Schematic Diagrams" show the reverse biased diode that will conduct the signal to ground in an ESD event. 

    Paul Shaffer said:
    Question 2:  Have any ESD failures ever occurred for the Redriver IC TI part number DS15BR400TSQ/NOPB?  If yes, what were the failure modes?

    ESD events on the DS15BR400 will be similar to the SN65LVDS96. The signal will be shorted to ground.

    Best,

    Jack