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INA219 ESD protection

Matt Hamilton
Prodigy 30 points
Other Parts Discussed in Thread: INA219

Hi All,

  I'm using an INA219 as part of a project to monitor the voltage/current on a 12v 110Ah battery. The INA219 is part of a breakout board by Adafruit:

http://www.adafruit.com/products/904

I've removed the 100R resistor there and using an external 50A 75mV shunt.

All was going well until suddenly it has stopped worked. I had switched the system off, then half an hour later switched it back on again, but looks like somehow may have damaged something. Vcc is 5V yet for some reason I'm now seeing a PD of 1V when measured between Vcc and GND with the INA219 board attached (removing it and the PD is 5V, so I know the rest of the system is fine).

I see reference to the INA219 having some kind of ESD protection that can be triggered by high dV/dt. I'm wondering if I might have triggered that somehow. Can anyone elaborate on what the protection is? Does triggering it damage the chip? Can is be reset?

Thanks

-Matt

  • 0
    TI__Mastermind 25865 points

    Hello Matt,

    Yes, the INA219 has ESD protection. However, I have a few questions first:

    a) What is your load current? Are you drawing 50A through the shunt resistor?
    b) Do you see any damage to the board itself?
    c) What does 'PD' stand for?
    d) I assume you're building this on a protoboard...have you tried a new location on the protoboard?
    e) Have you tried replacing the device? You can order free samples using the following link:

    http://www.ti.com/product/ina219#samplebuy

  • 0 in reply to Pete%20Semig
    Prodigy 30 points

    A) my intention is to run up to 50A through my shunt (75mV) but in this instance I was only drawing max 4A

    B) I can't see any damage by eye. I am however now measuring only 6 ohms between vcc and ground. I've yet to isolate the chip from the rest of the circuit through so still a chance there could be a bridge elsewhere although I can't see one. 

    C) Potential Difference

    D) Yes it is on a proto board. I've not tried to unsolder it and move it yet. 

    E) Not tried replacing it. My solder skills are not up to surface mount level. Hence why I bought the INA219 as part of the breakout board as per the link above. 

    So what does the ESD protection do? And is it resettable?

    -Matt

  • 0 in reply to Matt Hamilton
    TI__Mastermind 25865 points

    Hello Matt,

    Thanks for the quick response.

    I doubt that turning the system on triggered and damaged the ESD structures of the device. The ESD structures require very fast high-voltage transients in order to trigger. However, if proper ESD precautions are not followed (e.g. using an ESD strap), the device can be damaged by simply touching it with your finger. Once a device is damaged it needs to be replaced.

    Perhaps your protoboard is not rated for 4A of current. Please ensure that all elements in the high-current path are rated to handle such current. I do not necessarily suspect an issue with the adafruit board for the sense resistor appears to be Kelvin-connected.

  • 0 in reply to Pete%20Semig
    Prodigy 30 points

    I have actually unsoldered the 100R sense resistor and removed it. I've the run wires from the board to a standalone 50A shunt which is in the path of the main current flow. 

    -Matt