TCA9406

The TCA9406 from Texas Instruments is a 2-bit bidirectional translator for SDA and SCL lines in I2C applications. It provides voltage translation between logic signal levels, operating from 1.65 V to 3.6 V on the A-side (referenced to VCCA) and 2.3 V to 5.5 V on the B-side (referenced to VCCB). This allows seamless interfacing between different voltage rails, including typical 1.8-V, 2.5-V, 3.3-V, and 5-V systems.

The device features an output enable (OE) input that can be tied directly to VCCA or controlled by a GPIO. When OE is low or VCC is at 0 V, all SCL and SDA pins enter a high-impedance state, significantly reducing quiescent current. The TCA9406 includes internal 10-kΩ pullup resistors on all SDA and SCL pins, simplifying external circuitry.

It supports standard I2C speeds up to 1 MHz and can handle up to 2 Mbps in normal operation. When used as a general-purpose level translator with push-pull devices, it can support speeds up to 24 Mbps. The TCA9406 offers excellent ESD protection, with up to 8-kV HBM on the B port and 2.5-kV HBM on the A port.

Available in SM8, US8, and DSBGA packages, the TCA9406 is suitable for various space-constrained applications. Its VCC isolation feature ensures both ports are in a high-impedance state if either VCC input is at GND, and no power-supply sequencing is required, offering design flexibility.