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DS90UB913/914 Application Question

Bernd S.
Prodigy 85 points

Hello,

i got a question regarding the PDB pins. What is the voltage level i have to tie the pin via the RC-circuit? In the datasheet LVCMOS is mentioned as type of voltage level( in my case 3,3V). But the MODE pin is of the type LVCMOS as well though requires the voltage level of 1,8V so i´m a bit confused.

Sincerely,

Bernd

  • 0
    TI__Expert 7395 points

    Hi Bernd,

    On the DS90UB913/4, the PDB and MODE are different I/O types. The PDB pin is a standard LVCMOS input type in which the input voltage threshold is set by the VDDIO supply. i.e. if VDDIO is 3.3V, then the PDB VIH/VIL threshold would be >=2V/<=0.8V respectively. On the other hand, the MODE pin (also includes IDx pin) is categorized as an analog input in which the referenced to 1.8V. Basically the input voltage is decoded into a specific mode based on the voltage divider. Note the MODE pin is only set upon power up or on reset.

    Dac Tran

    SVA / APPS

  • 0 in reply to Dac Tran
    Prodigy 85 points

    Ok thank you for your answer.

    But please update the datasheet regarding this matter. MODE is not declared as type analog. Second question. What does "w/ pull down" for example mean? Are the resistors (pull-up or pull-down) integrated or is this an application hint, that you have to use a pull down externally? I think you have to add them externally but once again i'm confused with the information in the Pin Descriptions. A little footnote would make the difference.

    Thank you,

    Bernd

  • 0 in reply to Bernd S.
    TI__Expert 7395 points

    Hi Bernd,

    Sorry for the confusion. I will submit the request to revise the datasheet.

    As for the pullup/pulldown pin references, these are internal active pullup/pulldown circuits within the LVCMOS pins. This is to avoid unknown states if the pins are left floating.

    Dac Tran

    SVA / APPS