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DRV5032: Wired-OR Usage

Part Number: DRV5032

Hi, I'd like to use the DRV5032 in a magnetic keypad. Just like a normal keypad, the switches would be muxed into an MxN array, where you'd drive the first column, and the read the rows, drive the next column, and then read the rows, etc.

The question I have is whether or not an DRV5032 with an open-drain output could have 3.3V applied to the output while the power to the part is off. If the part functioned as shown in the figure 8.2 diagram, then the output mosfet would be fine. And a discrete implementation of the circuit would be fine. But of course there can be parasitic diodes that will result in leakage back to the DRV5032 core. Thus, my question.

The absolute max ratings suggest this cannot be done. But it's such a useful mode of operation for an open drain circuit I thought I'd ask.

  • Hi SeattleEE,

    While power to the device is off the output should be as well. Device damage will occur if the abs max specs are exceeded.


    Thank you for choosing TI parts,
    Manuel Chavez
  • OK, thanks, understood. If hall sensors make sense to detect a single key closure (and they do!) then they will also make sense for detecting an array of keys. In the future, it would be very helpful if the open-drain parts could cope with a voltage at the output when off (or disabled, although these parts are so low-powered already that an enable pin might seem silly).