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INA282: Negative supply voltage on V+ pin

Part Number: INA282

Hello Expert,

Due to the leakage voltage of the customer board, about -0.7V negative voltage is supplied to V+ pin of INA282 during initial 80s when INA282 board start-up. And then V+ pin voltage goes up to 5V. Is this -0.7V negative voltage on V+ pin during 80s may cause problem in the device?

Best regards,

Alice

  • Hi Alice.

    that's not good. Could result in latch-up. If it's only leakage current that causes this -0.7V, then a simple resistor to GND should solve the issue. Or, add a 1A...3A Schottky diode, reversely wired from V+ to GND.

    Kai
  • Hello Alice,

    Thanks for reaching out on the forum.  I agree with Kai on this.  I suspect that the INA282's internal ESD structure might be preventing the voltage from actually dipping lower.  ESD structures are meant for suppressing quick transients.  As such, a transient that exceeds a minute (80s) with the diode dumping alot of current to regulate the voltage will likely dissipate a substantial amount of power in the form of heat that can either immediately destroy the ESD structure or degrade the ESD structural integrity over time and degrade the overall device performance over time.  One possible way to test if the ESD structure is turning on would be to disconnect the INA282 supply and see what potential that sourcing trace actually goes to at startup.  If you see this potential drop even further below -0.7V, you should add a diode like Kai said.

  • Hello Patrick and Kai,

    I sent you an separate email about this topic. Could we have further email discussion about this?

    Best regards,
    Alice