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SN65HVD76: Start Delay by DE signal

Macs
Expert 3910 points
Part Number: SN65HVD76

Hello Team:

Could you tell me Driver output delay from DE signal related to Receiver side?

One of customer mentioned that he has two Sn656HVD76 driver used, and one of them has active receiver, that means /RE=Low and always active,

However, one more driver has inactive receiver which means /RE=High always.

And He measured that Driver active quick with receiver active,(10's nano sec. order)
But, if receiver is non-active(/RE=High), Driver starts slow( 8us)

This is may be related to " PZH, tPZL Driver enable time"?

Thanks

  • 0
    TI__Intellectual 1520 points

    Hi Mac,

    thank you for reaching out. As displayed in 7.10 Switching Characteristics on page 9 of the datasheet these values are in spec of the device.

    So this is the time the driver needs to drive or pull down the Vo ouptut after the enable signal is occurring at the DE pin.

    The huge time difference between a enabled/disabled receiver comes from the fact, that the internal band-gap etc. is completely shutdown when the receiver is disabled. All the current for these internal circuits need to build up when the DE signal is starting the device. Other with an enabled receiver, only the driver circuit needs to build up current.

    I hope this helps to understand this behavior more, let me know if you need anything else.

    Kind regards 

    Dierk