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TMP100: TMP100

Mark Tillmann
Prodigy 110 points
Part Number: TMP100

Per the datasheet, leaving the address pins floating will provide additional device addresses.

If pull-down resistors are used to provide a "0" state, is 220 ohms an adequate pull.

i.e. I am unsure of the internal address circuitry that allows a "float" state to provide a 3rd logic level.

Thanks for your time!

Mark

  • 0
    TI__Mastermind 28070 points

    Hi Mark,

    Thank you for your post and welcome to the Sensors Forum.

    A pull up or pull down resistor is not necessary to make the address connections, these pins can be connected directly to VDD or GND, or just left disconnected. We do often see 0-ohm resistors used when the ability to change addresses is desired, but it is not a requirement. 

    The only invalid combination is floating both pins (per table 2 in the datasheet). At least one of the pins should be connected for the address detection to function properly. 

    Best Regards,
    Brandon Fisher

  • 0 in reply to Brandon Fisher94
    Prodigy 110 points

    Hi Brandon,

    Thanks for the response.

    I am a test engineer looking at a customers new design.  I would like the ability to toggle the lines with a digital driver.  This would not be possible with a 0ohm pull-down.  Would using a 220ohm pull-down instead of a 0ohm pull-down introduce any risk to the design?

    Thanks for your time,

    Mark

  • 0 in reply to Mark Tillmann
    TI__Mastermind 28070 points

    Hi Mark,

    As an update. I'm still checking on this with our design team. Currently i suspect that it won't work, but I'll have a final answer for you before Friday. 

    Best Regards,
    Brandon Fisher

  • 0 in reply to Brandon Fisher94
    TI__Mastermind 28070 points

    Hi Mark,

    Based on what i've found this will work with 220 ohms, but only if you just care about the 1 and 0 set values. If you want to have the float address settings available you will need a larger pulldown resistor.

    In my test setup i found that 47kOhm was the minimum for this to work. I'd recommend going higher (100kOhm or so) for some additional margin. 

    Best Regards,
    Brandon Fisher

  • 0 in reply to Brandon Fisher94
    Prodigy 110 points

    Perfect!

    Thanks for the response and your time Brandon!

    Merry Christmas!