In our design, PCA9306 is doing the I2C bus level shifting from +3.3V I2C bus to +1.8V I2C bus.
We want to use +3.3V I2C bus to talk UCD9081 to enable +1.8V power rail which is requried by PCA9306.
The problem is: before +1.8V is enabled, +3.3V I2C bus is dead because PCA9306 pull down +3.3V I2C bus to +2.2V.
We have pull up resistors on both +3.3V and +1.8V side.
Please let us know what is the problem for this.
Many thanks.
David.