What the PCA9517AD,118 does on the bus
The NXP PCA9517AD,118 is a 2-channel I²C buffer and repeater (ReDriver) that isolates bus capacitance and allows longer traces or more devices on an I²C bus running up to 400 kHz. It sits between two I²C segments, regenerating the bus signals so that the total capacitive load on each segment stays within the 400 pF Fast-mode limit.
Supply voltage and level-shifting capability
Input capacitance is 6 pF per channel, which adds negligible load to the upstream segment.