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SN65HVD96: SN65HVD96

divyanshu bawa
Expert 1325 points
Part Number: SN65HVD96
Other Parts Discussed in Thread: SN65HVD888, SN65HVD1782, TCAN4420

hi,

I am going to use Sn65hvd96 for my next design Replacing Sn65hvd 1782. I want to know some of the points related to this IC, I need a application schematic for SN65HVD96  with proper components values.If by mistake i put 24v and gnd in place of A and B what protection i can give externally. I was thinking to give same as that of Sn65hvd 1782 by putting SM712 tvs diode. If u can provide me with some other protection it would be beneficial.

Kind Regards

Divyanshu 

 

  • 0
    TI__Guru 62920 points
    Hello,

    Please note that SN65HVD96 is not a direct replacement for SN65HVD1782. It uses a different signaling scheme that is intended to be able to be inverted (swapping each half of the differential pair) without losing the ability to communicate. I wanted to make sure you understood this before proceeding. (If you would like an RS-485 compliant device that can tolerate mis-wirings, I'd recommend considering SN65HVD888.)

    Protecting against higher-voltage DC shorts can be tricky. A TVS diode like SM712 would clamp the voltage, but would likely be damaged if exposed to the short-circuit conditions for an extended period. (TVS diodes are intended to protect against transient stresses, not DC.) You could use a series resistance in order to limit the current while the TVS is clamping, but you would need to be careful not to make the resistance too high or it could interfere with data communication. Some applications will use a PTC fuse for this kind of protection. It will have a low resistance normally, but when the TVS clamps and the current rises the heating in the fuse will cause its resistance to rise, helping to limit the fault current to manageable levels.

    Another solutions I could propose is TCAN4420. It is based on CAN rather than RS-485, but is able to withstand shorts to 24 V without external protection components. It can tolerate differential pair inversions as well.

    Please let me know if you have any questions on this.

    Regards,
    Max
  • 0 in reply to Miguel Robertson
    Expert 1325 points
    Hi max

    I’ll look into Sn65hvd 96 protocol

    For short circuits thing can I provide bidirectional Smbj26v diode at the input. If it gets shorted the current will follow the low resisitabce path and my device will be protected. Here the device is buck converter iam talking. About
  • 0 in reply to divyanshu bawa
    TI__Guru 62920 points
    That diode doesn't break down until ~32 V, so depending on the current it needs to sink the peak clamping voltage might be higher than the absolute maximum limit of the SN65HVD96. You may want to double-check that and then see if some additional current-limiting resistance could be effective in preventing an over-voltage condition. If you meant that the diode is just for DC/DC converter protection then ignore this message.

    Regards,
    Max