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TXB0106 question ?

Other Parts Discussed in Thread: TXB0106

SCH.docxHi Team

My Question are write in Word file , Please help check

  • kerr - My feedback is below:

    kerr chang said:

    When initial, does the B side(net: SPI_SCK) is low to cause the 4K to GND? (and this is why we measured around 0.5V voltage which is divided 1.8v by 10K PU and 4K PD.)

    Yes. Each TXB0106 I/O has a 4k series resistor. If a TXB input is driven low, then its output resembles a 4k pulldown resistor to GND. That could act as a voltage divider and keep the line low. The 'Detailed Design Procedure' of the datasheet specifies that pullups or pulldowns, if needed, must be greater than 50k.

    kerr chang said:

    When does the one shot block active? And when one shot block active, it will cause the A side voltage keep on VCCA(1.8V)?

    You can read this app note to under the one-shot architecture.

    Best Regards,
    Nirav

  • Hi Nirav

    Looks like  the A site pull high resistor will impact A site output VOH and VOL, as my understanding, according to our application, is that means the A site pull high resistor 3.3K ohm is ok if A site APU_SPI_SCK is always input?

  • Kerr,

    In theory it should work. If the TXB0106 I/O is used exclusively as an input, then an external pullup resistor is acceptable as long as the SPI master can drive the TXB0106 I/O to valid VIH and VIL levels. I would like to verify this in the lab with a spot check just to make sure. I hope to get you results within 24 hours.

    Best Regards,
    Nirav

  • Kerr,

    I performed a lab spot check and verified that the above scenario will work. I connected a 10K pullup to one of the I/Os and used a Pattern Generator to overdrive the pullup with a 10 MHz clock. The output was also a 10 MHz clock.

    Best Regards,
    Nirav
  • Hi  Nirav

                     Thank you for your great support !!