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DS90UB914Q-Q1: Des-Ser 913/914

Part Number: DS90UB914Q-Q1

Hi TI support engineer:

We are to revise to a new board of Des.914Q (DS90UB914Q), which the last version did not work somehow. Now we have a confusion regarding the datasheet saying  input pins PDB ,BISTEN., OEN, OSS_SEL and SEL "have internal PULL DOWN" (datasheet page 7)", However , from the EVL board it looks like these are PULL UP not DOWN. Please advise if it is PULL UP OR PULL DONWN? and what are these internal resistors' value anyway?

See attached picture

Tom

  • Hello Tom,

    I am looking into this and will get back to you tomorrow.

    Regards,

    Carrie

  • Hi Carrie,

    thanks for your response. I am looking forward to your answer today. Also FYI: I did meansure my PCB with DES.914 the DC voltages on pin  BISTEN, OEN, OSS_SEL and SEL: it looks like the internal

    resistor is "pull down" (when I add external 10k PULL UP onto these pins, the DC voltage is HIGH, when I remove my external PULL UP 10K, the DC voltages on thes pins appear LOW). But what confused me is : the EVL board schematic, the dip-switch connected to GND. Why? (if these pins have internal pull down, why need this DIP switch connected to GND), I assume your EVAL board works.

    thanks,

    Tom

  • Hello Tom,

    Please pull the resistor up or down externally according to the mode you want, as shown in the EVM schematic. We have validated these resistor values and connections for the device.

    Regards,

    Carrie