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DRV10987: DRV10987 I2C spec

Christoph Schmidt38
Prodigy 30 points
Part Number: DRV10987

Dear all,

does I2C-interface of the DRV10987 is compliant to the I2C-standard with regard to the electrical specification?

I read in the datasheet VI2C_L, Inputlow, is maximum 0.6 volts.

The I2C standard says the maximum low level input voltage is 0.3xVDD. For 3.3 volts supply this would mean 0.99 volts max low level input voltage.

I want to use an I2C isolator and this chips has the output low spec min 600mV to max 900mV on one side.

Is the datasheet of the DRV10987 really true in this case?

Best regards

Christoph Schmidt

  • 0
    TI__Mastermind 19720 points

    Hi Christoph,

    The DRV10987's I2C interface will follow the following section of the datasheet:

    What I2C isolator are you using and I can check if it will be compatible with our device?

    Regards,

    Michael

  • 0 in reply to Michael.Walker
    Prodigy 30 points

    Hi Michael,

    thank you for your reply.

    I'm using the ADUM1250 from ADI.  Normally we use thís chip with side 1 to the I2C participants and side 2 to the bus. But from my point of view I don't think that I can connect the DRV10987 to side1 of the ADUM1250. But I will check whether I can switch the sides in my application case.

    Regards,

    Christoph

  • 0 in reply to Christoph Schmidt38
    TI__Mastermind 19720 points

    Hi Christoph,

    The side 2 should be compatible with the DRV10987 since the Logic low output voltage is at max .4V and the DRV10987's input low voltage is .6V. 

    Regards,

    Michael

  • 0 in reply to Michael.Walker
    Prodigy 30 points

    Hi Michael,

    I want to connect side 1 to the DRV10987. And this is not possible, do you agree?

    I can connect side 2 to the DRV10987, but then I have the modified logic levels of the ADUM1250 side1 from time to time on the rest of the bus. I'm not sure whether this is safe, but this I have to clarify for myself.

    Regards

    Christoph

  • 0 in reply to Christoph Schmidt38
    TI__Mastermind 19720 points

    Hi Chistoph,

    I think the DRV10987 will work with side 1 of the ADUM1250 because in the datasheet I think they are assuming you are using a small resistor pull up of 1K rather than the 4.7K that we recommend for our device. This means that the ADUM1250 will have to pull less current and will have a lower output voltage. I can not say for certain though because their datasheet is unclear. 

    In their datasheet they say that their device's Side 1 is I2C compatible and Side 2 is I2C Compliant.  Our device is I2C compatible as well, so I do not think I can definitively say that the I2C compatible side 1 and our I2C compatible interface will be able to work across all implementations. but I can say that they will probably work with a 4.7K pull down. 

    Regards,

    Michael