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PCA9306: Clarify allowed level translation

Shu Khan Lee
Prodigy 60 points
Part Number: PCA9306
Other Parts Discussed in Thread: TCA39306

Hi

From PCA9306 datasheet, the recommended operation condition in section 6.3 stated that the Vref1 range can be lower than 1.2V.

In Design requirements section 9.2.1, Vref1 min is stated as 1.2V.

May I know if this part suitable to use for translation from 1.05V -> 2.5V/3.3V or 1.1V -> 2.5V/3.3V?

If no, please recommend a suitable part for I2C bus translator. Thanks.

  • 0
    TI__Guru 56710 points

    Hi Shu,

    Shu Khan Lee said:
    May I know if this part suitable to use for translation from 1.05V -> 2.5V/3.3V or 1.1V -> 2.5V/3.3V?

    PCA9306 can technically support this voltage range from a functional standpoint, TCA39306 a similar device that modifies the datasheet to show support down to 0.85V on Vref1 in the recommended operating conditions. I would recommend the TCA39306 just so that you can be within datasheet specification.

    -Bobby

  • 0 in reply to BOBBY
    Prodigy 60 points

    Hi Bobby

    So PCA9306 can be used for 1.05V translation, just the spec not clearly show in datasheet?

    Another question:

    Is TCA39306 is built with same structure and have same performance as PCA9306?

  • +1 in reply to Shu Khan Lee
    TI__Guru 56710 points
    Shu Khan Lee said:
    So PCA9306 can be used for 1.05V translation, just the spec not clearly show in datasheet?

    It can work, it kind of depends on the drive strength of the external open drain driver and the pull up resistors you use (I'm assuming you are using this for I2C/SMBus applications).

    I recommend the TCA39306 mainly because 1.05V isn't technically supported in the datasheet so if you run into issues, TI may not provide support troubling shooting or approving quality returns if the device was used outside of the recommended operating conditions.

    Shu Khan Lee said:
    Is TCA39306 is built with same structure and have same performance as PCA9306?

    TCA39306 is the newest version of the PCA9306 with better Ron parameters. So I would say TCA39306 a slightly improved version of PCA9306. 

    -Bobby