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Original question:

SN65HVD1473: Switching between full and half duplex

SN65HVD1473: Using SN65HVD1473 to switch between half and full duplex

Christina Lim
Expert 6405 points
Part Number: SN65HVD1473


HI All,

I had a customer whom is interested to implement similar switch betwee half and full duplex discussed in below thread.

However, I had a question on the handling of RS485 below GND. Would the multiplexer/switch CD4053 be able to handle voltage <0V?

Thanks,

Christina

  • 0
    TI__Guru 62920 points

    Christina,

    I'll notify the team responsible for the CD405xB so that they can confirm, but my understanding is that it can only be low-resistance for analog signals between VEE and VDD.  So, if VEE is at 0 V it would restrict the allowable common mode range of the RS-485 signaling.  This may be OK in applications that do not need the full -7 V / +12 V range – i.e., ones where the GND references of each node are connected together with minimal voltage drops.  If a wider signal voltage range is needed, though, use of a photo-relay would be an alternate solution.

    Regards,
    Max