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Pca9306: Works without Rpu at SCLK2 and SDA2

Ting Ye
Genius 11800 points
Part Number: PCA9306
Other Parts Discussed in Thread: TCA9406, TCA9803

Hello Team,

May I know if PCA9606 I2C level shift communication will work if there is no Rpu at 2nd side?

There is no block diagram shows where VREF2 connects. So it is not easy to tell if without 2nd Rpu the IC will work.

And may I know if there is other I2C level shifter integrated Rpu and is p2p to PCA9306?

Thank you.

Regards,

Ting

  • 0
    TI__Guru 60042 points
    Ting,

    If there are no pull-up resistors on the 2nd side, communication will not be possible. The second side isn't driven to the high level, only the low, and there aren't internal pull ups, so the external pull up resistors are necessary to output a logic high on the 2nd side.

    We don't have any pin to pin I2C level shifters with integrated pullup resistors and bidirectional communication. There is the TCA9406 that has bi-directional communication, faster switching frequency, and internal pull up resistors, so external ones aren't necessary, but it is not pin to pin compatible.

    Regards,
  • 0
    TI__Prodigy 255 points

    Hi Ting,

    Eric is correct that we do not have a level shifter that can operate without Rpu.

    However, we do have a new repeater that has level shifting capability that allows you to remove Rpu on 2nd side - check out the TCA9803. This device has new architecture that allows us to provide improved signal integrity while removing Rpu. This would work for your application, even if you do not need the repeater function, as it can also be used as a level shifter.

    Let me know if this will work for you.

    Regards,

    Kaitlyn Mazzarella