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PCA9306: I2C 3.3V <-> 2.8V translator (PCA9306 ?)

Part Number: PCA9306


I've seen a related thread on here (it's locked so I could not respond) claiming that the PCA9306 can do 3.3V <-> 2.8V level translation on an I2C bus. The posts references figure 5 (which in the current datasheet is a 1.8V <-> 3.3V translation application).

I would like to double-check that this use case is possible. On page five there is a note saying "To support translation, VREF1 supports 1.2 V to VREF2 - 0.6 V. VREF2 must be between VREF1 + 0.6 V to 5.5 V." Which would imply shifting 3.3V <-> 1.8V would violate this requirement (assuming VREF2 = 3.3V, VREF1 has to be 1.2V to 2.7V).

If the PCA9306 cannot do 2.8V <-> 3.3V conversion please suggest a part, if possible. Board area is a significant consideration for my current design.

Thank you,


  • Hi Andrew,

    Technically the device preforms best when there is a threshold voltage difference between VREF2 and VREF1. This is because VREF2, in translation mode, is tied to the gate of the pass transistor in the device.

    However, this device can still support the translation if it is within the threshold voltage difference. There may be some losses in speed but nothing significant especially at a difference of 0.5V.