Bidirectional buffer enables I2C/SMBus systems to be extended with no performance loss

The Texas Instruments TCA9517-Q1 is a bidirectional buffer with level shifting capabilities for I2C and SMBus systems. It supplies bidirectional voltage-level translation (up-translation/down-translation) between low voltages (down to 0.9V) and higher voltages (2.7V to 5.25V) in mixed-mode applications. The device allows I2C and SMBus systems to be extended with no loss of performance, even during level shifting. The device buffers both the serial data (SDA) and the serial clock (SCL) signals on the I2C bus, thus providing two buses of up to 400pF bus capacitance to be connected in an I2C application. The device has two types of drivers: A-side drivers and B-side drivers. All inputs and I/Os are overvoltage tolerant to 5.25V, even when the device is unpowered (VCCB and/or VCCA = 0V). The buffer design on the B-side prevents its use in series with devices that use static voltage offset. The devices do not recognise buffered low signals as a valid low and do not propagate it as a buffered low again.