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TXB0108: Fan out to multiple devices

Part Number: TXB0108
Other Parts Discussed in Thread: TXU0204, SN74LVC1G34

hello.

I intend to use the TXB0108 to translate my FPGA signals (1.8V) to/from several other components (3.3V)

My problem is as follows:

Most of these signal are 1:1, meaning one pin from the FPGA goes to one pin on a components. here I don't see any future problem.

However, 3 of there pins are 1:8. meaning of these pins will be connected to 8 components. In addition, these pins are only one direction (The "1" will always be output, and the "8" will always be input)

I was going to use one of the remainder pins of the TXB0108 to fan out to the 8 inputs, but now I'm thinking it may not work, and maybe I should either fan out to the TXB0108 (Instead of from the TXB0108, meaning FPGA pin to 8 different pins on the TXB0108) Or just use a different component, such as the TXU0204 or similiar.

Can you recomment me the next step?

Thank you.

Gady Wollmann

  • For unidirectional signals, you should use a unidirectional translator (i.e., any TXU device).

    A TXB might be able to drive eight other inputs as long as the traces are not too long. When in doubt, insert a buffer (e.g., SN74LVC1G34/125).

  • Hello

    I have both unidirectional and bidirectional directional signals, and the intention was to keep this option open also for future use.

    SInce the design is almost over, I have added the buffers, and these signals will always be unidirectional.

    Thank you for this advise.