Using a PCA9306 voltage-leveler with an MCU and a 5.5v arduino sensor
The PCA9306 is a voltage translator for I²C, which is a purely digital protocol. In other words, it translates a voltage of 0 V to 0 V, and a voltage of VREF1 to/from VREF2, and any other voltages are forbidden.

If you have an analog signal that can be anywhere between 0 V and 5 V, you need to use an analog amplifier (with an amplification factor of less than one) to proportionally reduce all possible voltages; see, e.g., Analog voltage level conversion (level shift).

If your sensor output has a very low impedance (which is unlikely), a voltage divider would be a simpler alternative.