4 Extend I²C Communication Distance by P82B715

Similar with P82B96, the P82B715 is another device for buffering highly capacitive I²C bus systems, and it supports bidirectional data transfer through the I²C bus too. The P82B715 buffers both the serial data (SDA) and serial clock (SCL) signals on the I²C bus and allows for extension of the I²C bus, while retaining all the operating modes and features of the I²C system. The main feature of P82B715 is

• Operating Power-Supply Voltage Range of 3V to 12V
• Supports Bidirectional Data Transfer of I²C Bus Signals
• Allows Bus Capacitance of 400 pF on Main I²C Bus (S_x/S_y Side) and 3000pF on Transmission Side (L_x/L_y Side)
• Dual Bidirectional Unity-Voltage-Gain Buffer with no external directional control required
• Drives 10× Lower-Impedance Bus Wiring for Improved Noise Immunity
• Multi-Drop Distribution of I²C Signals Using Low-Cost Twisted-Pair Cables
• I²C Bus Operation Over 50 Meters of Twisted-Pair Wire

The typical application for P82B715 as Figure 4-1 shows.

Figure 4-1 Long-Distance I²C Communications based P82B715

Compared to P82B96, two or more S_x or S_y I/Os of P82B715 can be interconnected and are also fully compatible with bus buffers that use voltage level offsets (such as the TCA9517) because this duplicates and transmits the offset voltage. See Figure 4-2 .

Figure 4-2 Long-Distance I²C Communications based P82B715