The NCT5927W is a CMOS integrated circuit that provides bidirectional level shifting between higher voltage (2.2 V to 5.5 V) and low voltage (down to 0.8 V) up to 1MHz for 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. The SDA and SCL pins are 5V tolerant and are high-impedance when the NCT5927W is unpowered.