The FA8202AOTR is a dual bidirectional I2C and SMBus voltage-level translator with an enable (EN) input and is operational from 0.7V to 5.5V for VREF1 and VREF2.
It allows bidirectional voltage translations between 0.7V and 5.5V, without the use of a directional pin. The low ON-state resistance (RON) of the switch ensures the connections be with minimal propagation delay. When EN is high, the translator switch is ON, and the A I/O are connected to the B I/O, respectively, allowing bidirectional data flow between ports. When EN is low, the translator switch is off, and a high impedance exists between ports.
In I2C applications, the bus capacitance limit of 400pF restricts the number of devices and bus length. The capacitive load on both sides of the FA8202AOTR must be considered when approximating the total load of the system, ensuring the sum of both sides is under 400pF.
All channels of the FA8202AOTR have the same electrical characteristics, and there is a minimal deviation from one output to another in voltage or propagation delay. This is a benefit over discrete transistor voltage translation solutions since 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. In a standard I2C system, pull-up resistors are required to provide logically high levels on the translator’s bus. The size of these pull-up resistors depends on the system, but each side of the repeater must have a pull-up resistor.
When the A port is low, the clamp is in the ON state, and a low resistance connection exists in the B port. Assuming the higher voltage is on the B port, when the B port is high, the voltage on the A port is limited to the voltage set by VREF1. When the A is high, the B port is pulled up to the supply voltage by pull-up resistors. This function allows a seamless translation between higher and lower voltages selected by the user, without any directional control.