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SN65HVD10-EP: SN65HVD10-EP

Paul Schwerman
Prodigy 30 points
Part Number: SN65HVD10-EP
Other Parts Discussed in Thread: SN65HVD10, THVD2450, THVD1450

I am analyzing a SN65HVD10MDREP in a circuit that has external protection on the outputs of the device. I need the characteristics of the internal 16V clamps to determine if my circuit will pass or not. Does anyone have the room temperature tolerance, the temperature coefficient and effective series impedance available for the 16V internal clamps? Or is a plot of voltage vs current on the 16V clamps available? I need to analyze it in a circuit that doesn't have a series 100 ohm with the applied voltage transient

  • 0
    TI__Mastermind 25705 points

    Paul,

    Unfortunately the internal ESD cells are not characterized individually. The clamps work with the circuitry to provide 16kV HBM protection. The clamps don't snapback and operate like diodes. What kind of transient do you expect?

    Regards,

    Hao 

  • 0 in reply to Hao L
    Prodigy 30 points

    This is not an ESD transient. It is coupled core wire current from current flowing on the shield over the twisted pairs. The  SN65HVD10 has a voltage input range, transient pulse on A and B of +/- 50V through 100 ohm for 15usec. I have an electromagnetic compatibility test that drives the part with a lower impedance (less than 100 ohm).

    I need to know the characteristics of the internal 16V clamp so I can covert the energy transferred in the data sheet to the part to the energy transferred in the test setup I have to analyze. If the new test setup delivers more than the rated joules into the 16V zener, I'll need to know the voltage/current curves for the internal 16V clamps so I can design an external clamp to protect the part.

    If the 16V zener is 16.0V +/- 8% at room temperature and has +9.2mV/C temperature coefficient, at -40C junction the clamp could be 14.12V with a series resistance of TBD. If analysis shows an external clamp is needed at the max zener voltage, the clamp would have to clamp to a voltage below the min zener voltage of 14.1V to protect the part.

    -Paul

  • 0 in reply to Paul Schwerman
    TI__Mastermind 25705 points

    Paul,

    Thanks for your explanation. Unfortunately I don't have any related data to provide. If I had some data, I would not suggest designing the system relying on it. The clamp's variation is not well controlled. If you need a 3.3V RS-485 transceiver with higher ESD level (more transient current capability), you may want to check out THVD1450 and THVD2450.

    Regards,

    Hao

  • 0 in reply to Hao L
    Prodigy 30 points

    Unpowered part is going into latch up on negative sweeps with the curve tracer before it reaches 16V negative.

  • 0 in reply to Paul Schwerman
    TI__Mastermind 25705 points

    Paul,

    Thanks for taking the data. Actually the bus pins have -9V and 14V abs max. When the negative voltage goes to -12V, the internal ESD clamp is triggered. As the ESD is clamped, it snaps back to -2V (holding the bus). The positive and negative are not symmetric in structure.

    Regards,

    Hao