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    Can I use a connector meant for differential signals for single-ended signals?

    Might be a dumb question, I had just assumed the answer would be yes, but I wanted to make sure before I made a terrible mistake.

    I need to send both differential and single-ended signals between two boards, and was going to use a samtec QTH-DP connector.
    I don't want to use two separate connectors if i can avoid it. Can I use those differential pins for single ended signals?

    •   Alt18th March 2017, 15:56

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    Re: Can I use a connector meant for differential signals for single-ended signals?

    Hi,

    I don`t expect problems.

    But in detail it depends on the (single ended) signals.. and on what information and precision you are interested in. (frequency, waveform, crosstalk....)

    Analog signal examples:
    * a 50 Hz signal coming from mains just for generating a zero cross information is not critical
    * and audio signal is more critical
    * an ultrasonic signal even more critical.

    And similar are digital signals: it depends on what you are interested in.
    * digital signal just to switch ON/OFF a relay is not critical
    * but you need to treat a digital signal very carefully if you want to measure ringing and overshoot.. (but then the application has some analog HF character)

    Klaus



    •   Alt18th March 2017, 16:56

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  3. #3
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    Re: Can I use a connector meant for differential signals for single-ended signals?

    Along with what KlausST mentioned, differential connectors are designed to not change the differential impedance between designated pairs of pins (like 100ohm for LVDS) as it goes through the connector, so if you have critical signals that you absolutely do not want to couple to another unrelated signal, don't put them on a differential pair, run ground (or perhaps leave it unconnected) on the other pin of the pair for that critical signal.



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