The I2C bus is used in a wide range of applications because it is simple to use. The bus consists of a two-wire communication bus that supports bidirectional data transfer between a master device and several slave devices. The master, or processor, controls the bus, specifically the serial clock (SCL) line. Data is transferred between the master and slave through a serial data (SDA) line. This data can be transferred in four speeds: standard mode (0 to 100 kbps), fast mode (0 to 400 kbps), fast-mode plus (0 to 1 Mbps), and high-speed mode (0 to 3.4 Mbps). The most common speeds are the standard and fast modes.
The I2C bus operates in bidirectional, half-duplex mode, while standard digital isolators are unidirectional devices. To make efficient use of one technology supporting the other, external circuitry is required that separates the bidirectional bus into two unidirectional signal paths without introducing significant propagation delay. These devices have their logic input and output buffers separated by TI's capacitive isolation technology using a silicon dioxide (SiO2) barrier. When used in conjunction with isolated power supplies, these devices block high voltages, isolate grounds, and prevent noise currents from entering the local ground and interfering with or damaging sensitive circuitry.