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SN65HVD1780: Pin capacitance for Digital Inputs pins

Brian Park
Prodigy 380 points

Part Number: SN65HVD1780

Looking for pin capacitance for Digital Inputs pins.  Info not on datasheet.

  • 0
    TI__Guru 62920 points
    Hi Brian,

    We'll need to look into this and get back to you next week.

    Max
  • 0 in reply to Miguel Robertson
    TI__Guru* 78271 points
    Brian,

    I've received samples for the device and just put it on a breakout board. I should be able to get you the measurements Monday morning (USA).

    Thanks,
    -Bobby
  • 0 in reply to BOBBY
    TI__Guru* 78271 points

    Brian,

    I connected the device to a mosfet pulling low on the Reset pin and then releasing allowing a pull up resistor (9060 ohms) to pull the signal up to Vcc (5V). I measured the 30% time value and 70% time value and looked at the difference which I call the rise time.

    Capacitance = t_rise/(0.8473*pullupresistor)

    Measurement of just my set up below (no device connected)|| capacitance comes out to 186.7pF

    ||Connected to the test set up||

    (with RE' pin connected)|| capacitance comes out to 191.5pF

    (with DE pin connected)|| capacitance comes out to 196.6 pF

    (with D pin connected)|| capacitance comes out to 192.3pF

    The difference between the test set up and the measured pins gives us the capacitance values

    -----------------------

    RE' pin = ~4.8pF

    DE pin =~9.9pF

    D pin =~5.6pF

    -Bobby