The NXP PCA9517A 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.

Active high repeater enable input
Open-drain input/outputs
Lock-up free operation