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LM4930: output of IRQ pin

Daoyan Zhao
Expert 3605 points
Part Number: LM4930


Hi,

I want to make sure the output way of below IRQ pin, is it OD? And what is blow IRQ logic level when it's high? Thank you!

BR,

Daoyan

  • 0
    TI__Guru** 110395 points

    Hi Daoyan,

    IRQ pin logic states should be based on VIH/VIL as specified on the data sheet:

    I'm not clear on your first question, could you elaborate on that one?

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    TI__Expert 3605 points

    We have open drain (OD) output and some other way I mean I don't know how IRQ output and how to connect the surrounding circuits. Feel free to tell me if you have any question.

    BR,

    Daoyan

  • 0 in reply to Ivan Salazar
    TI__Expert 3605 points

    Hi Ivan,

    I want to add some, customer want to connect IRQ pin to MCU, and the controller connect pin support 1.0-1.8V, so customer want to know the IRQ pin output voltage level, your picture above is Digital input voltage level, is the digital output voltage level the same with the input voltage level? That is 0.4 & 1.4V, right?

    And I notice our app diagram, IRQ connect a jumper, and the jumper also connect ADR which has pull up Res on it, so I'm not sure if IRQ can connect directly to the pin of MCU. Thank you! 

  • +1 in reply to Daoyan Zhao
    TI__Guru** 110395 points

    Hi Daoyan,

    Unfortunately I don't have the device to test, and there is no evaluation module either so I cannot say for sure the IRQ pin voltage, after thorough look into the description, I think the voltage level of IRQ will be based on DVDD, and as the minimum allowed is 2.6V then I think you'll need a level translator for your 1.8V MCU input.
    In addition, I'd say this is not open drain output, most likely push-pull or similar as it seems to be able to drive the pin and does not mention an external pull-up required.

    J4 from the schematic is actually purposed to give an accessible connection to IRQ pin, along with a DGND reference point, not to place a shunt on it.
    Regarding the ADR and pull up resistor connection, that is not related to IRQ, as mentioned J4 only has connections to GND and IRQ.

    Best regards,
    -Ivan Salazar
    Applications Engineer