This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TXS0104E-Q1: DESIGN REVIEW

Part Number: TXS0104E-Q1
Other Parts Discussed in Thread: TXS0104E, SN74AHC244-Q1

Hello,

Kindly review the attached design using TXS0104EQPWRQ1
Thanks,

Melbin

8611.TXS0104EQPWRQ1_SCH_28DEC2020.pdf

  • Hello,

    We are working on a project with TXS0104EQPWRQ1 in it.
    Kindly review the attached schematics and let me know the review comments.

    TXS0104EQPWRQ1_SCH_28DEC2020.pdf

  • Hi Melbin,

    The TXS0104E has internal 10-kΩ pull-up resistors on all I/O ports (Ax and Bx), so the external resistors R145, R150, and R151 are not typically required and I would recommend to remove them under most circumstances. If the outputs are being disabled and you need to have them held in the high state, I would recommend to increase the resistor values up to 100 kΩ. This will maintain the output voltage as high when disabled, but not cause a significant current draw during normal operation.

    Otherwise the schematic looks good. I can't see the load, on either A or B port, so please take note that this device is very sensitive to heavy loads. You should maintain under 70pF at all I/O pins, and avoid long traces. Either of these can result in oscillations.

  • Part Number: TXS0104E-Q1

    Hello,

    Kindly review the attached design using TXS0104EQPWRQ1
    Thanks,

    Melbin

    TXS0104EQPWRQ1_SCH_28DEC2020.pdf

  • The TXS OE inputs are active high, so I would have expected pull-down resistors. Do you intend these devices to be active during power-up/-down (when the I/O states might be undefined)?

    The TXS has internal pull-up resistors at the I/Os. The external pull-ups are necessary only if the B side pins are used as outputs (which is not the case if I interpret the arrows correctly).

    The TXS is intended for high-speed bidirectional signals. If you have unidirectional signals that you want to translate to a lower voltage, you can simply use a buffer with overvoltage-tolerant inputs, such as the SN74AHC244-Q1.

  • Hey Melbin,

    As Clemens mentioned, this device isn't really necessary for unidirectional signals and you may be better suited with a buffer device like the one he suggested. Also, the pull-ups you have on the I/O will increase the Low DC offset (VIL and in turn VOL) so if that is a problem I recommend removing them if possible.

  • Melbin,

    I noticed that you have already posted this. In an effort to consolidate posts on E2E, I have merged the threads.

    Best,

    Danny