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HDC1000 - Pull up/down resistor for ADRx pins

Kawai
Guru 19775 points

Hi Team,

Could you please tell me the recommended pull up and pull down resistor for ADR0 and ADR1 pins ?

Regarding the User's Guide schematic, they were pulled down directly to GND.

I believe direct connection to GND would be okay, how about the pull up resistor value for ADRx=High ?

Best Regards,
Kawai

  • 0
    TI__Expert 6930 points

    Hi,

    Thank you for your question reagrding the pull-ups.  I will forward your question to the Applications Engineer responsible for this device.

     

  • 0
    TI__Genius 9655 points

    Hi Kawai,

    the ADR0 and ADR1 pins can be tied to GND or VDD without any pull-up or pull-down resistance (see DS, pin configuration section).

    In the EVM, as you have noticed, there are the footrpints of the resistances conencted to those pin just to allow the configuration of the address.

    In theEVM  user's guide we suggest to use 0ohm resistances (a short is fine) to populate those footprints.

    Regards,

    Domenico

  • 0 in reply to domenyko
    Guru 19775 points

    Hi Ed-san, Domenico-san

    Thank you for your support.

    I understood that you could directly tie ADRx pins to VCC or GND without a resistor.

    I have additional question.

    [Q2]
    If customer would like to use a pull up resistor, can you use 100kohm ?

    [Q3]
    What would be the maximum value which could be used for pull up and pull down resistor ?

    Best Regards,
    Kawai

  • 0 in reply to Kawai
    TI__Genius 9655 points

    Hi Kawai,

    if a customer wants to use a pull up or pull down resistor he can, even if the resistances are not requested. The I2C addres of the device needs to be fixed, in the DS we suggest to tie the pins to VDD or GND.

    ADRx pins are input digital pins so the amount of current which could flow is negligible and there isn't any risk to create weak pull down and pull up even with high resistances.

    To be honest I do not know which is the highest value of resistance that you can connect and I do not understand which is the benefit in this kind of topolgy.

    Regards,

    Domenico

     

  • 0
    Prodigy 10 points

    Hi Kawai

    I faced the same problem in my project, just want to know how did you go? Can you share a bit with me?

    Thank you 

  • 0 in reply to Juan Roybal
    TI__Genius 9655 points

    Hi Juan,

    why do you need the pull-down and pull-up resistance at the ADRx pin ?

    In the DS we suggest to tie those pins to VDD or GND.

    In the EVM there is the apprach with the pull-down and pull-up resistance jsut to offer the possibility to change the adrress in case someone wants to control multiple devices with one micocontroller.

    regards,

    Domenico