The PCA9517 is a CMOS integrated circuit that provides level shifting between low
voltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) I2C-bus or SMBus applications.
While retaining all the operating modes and features of the I2C-bus system during the
level shifts, it also permits extension of the I2C-bus by providing bidirectional buffering for
both the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF. Using
the PCA9517 enables the system designer to isolate two halves of a bus for both voltage
and capacitance. The SDA and SCL pins are over voltage tolerant and are
high-impedance when the PCA9517 is unpowered.