AD5667R ADDR pin unconnected - wrong I2C address?

Hi,

I noted that two AD5667RBRMZ-2, with ADDR not connected, did not react on the I2C address where A1=1, A0=0, but rather on A1=1, A0=1 - which corresponds to ADDR = GND according to the data sheet.

Connecting ADDR to GND doesn't change anything.

VDD is 3.3 V.

It's not a big deal, but what could be wrong?

Thanks

Michael

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  • 0
    •  Analog Employees 
    •  Super User 
    on Jun 21, 2021 1:26 AM

    Hi, 

    By "did not react", do you mean there's no ACK returned by the device? 

    Connecting ADDR to GND doesn't change anything.

    What do you mean by the statement above? At address A1=1, A0=1, the device still does not respond? 

    How about when you tie up ADDR to VDD?

    Can you give a scope shot of your serial comms with the AD5667R? 

    Best regards,

    Ian

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  • 0
    •  Analog Employees 
    •  Super User 
    on Jun 21, 2021 1:26 AM

    Hi, 

    By "did not react", do you mean there's no ACK returned by the device? 

    Connecting ADDR to GND doesn't change anything.

    What do you mean by the statement above? At address A1=1, A0=1, the device still does not respond? 

    How about when you tie up ADDR to VDD?

    Can you give a scope shot of your serial comms with the AD5667R? 

    Best regards,

    Ian

Children
  • Yes, by "did not react", I mean there's no ACK returned by the device. It also doesn't change to the desired output voltage.
    It only reacts on A1=1, A0=1, and then it fully works as expected.

    This is the same whether I leave ADDR open, or connect ADDR to GND. (Of course, the latter is the specified case.)

    I should add that "leaving ADDR open" in my case means: "don't connect the PCB trace to GND or VDD". There is always a PCB trace connected to the ADDR pin, because the device is soldered to a SOP10-to-DIL10 Prototyping PCB.
    Maybe that's the problem here?

    (The scope shot is kind of boring, it just shows a working standard I2C communication when the address bits are set to 11, and a non-ACKed communication when set to 10.)

    Thanks
    Michael

  • 0
    •  Analog Employees 
    •  Super User 
    on Jun 21, 2021 10:44 AM in reply to mh-

    Hi Michael,

    The PCB trace shouldn't be a problem as long as you assured that the pin is properly set to NC when you mean it to. Make sure that the PCB trace of the addr pin is not connected to any other parts of your circuit that might pull it to GND. 

    How about setting the addr pin to VDD? the device address bits will be 00 then. 

    Do you have other AD5667R devices? Does it happen to the 2 particular devices you mentioned?

    Best regards,

    Ian