This dual bidirectional I²C and SMBus voltage-level translator, with an enable (EN) input, is operational from 1.2-V to 3.3-V V_REF1 and 1.8-V to 5.5-V V_REF2.

The PCA9306-Q1 allows bidirectional voltage translations between 1.2 V and 5 V, without the use of a direction pin. The low ON-state resistance (r_on) of the switch allows connections to be made with minimal propagation delay. When EN is high, the translator switch is ON, and the SCL1 and SDA1 I/O are connected to the SCL2 and SDA2 I/O, respectively, allowing bidirectional data flow between ports. When EN is low, the translator switch is off, and a high-impedance state exists between ports.

In I²C applications, the bus capacitance limit of 400 pF restricts the number of devices and bus length. Using the PCA9306-Q1 enables the system designer to isolate two halves of a bus; thus, more I²C devices or longer trace length can be accommodated.

The PCA9306-Q1 also can be used to run two buses, one at 400-kHz operating frequency and the other at 100-kHz operating frequency. If the two buses are operating at different frequencies, the 100-kHz bus must be isolated when the 400-kHz operation of the other bus is required. If the master is running at 400 kHz, the maximum system operating frequency may be less than 400 kHz because of the delays added by the repeater.

All channels have the same electrical characteristics, and there is minimal deviation from one output to another in voltage or propagation delay. This is a benefit over discrete transistor voltage translation solutions, because the fabrication of the switch is symmetrical. The translator provides excellent ESD protection to lower-voltage devices and at the same time protects less ESD-resistant devices.