I2C Bus extender

     

    
     Sometimes I feel to communicate my data for long distance via an I2C bus communication. But unfortunately the I2C protocol supports very few meters only. As a normal application interfacing such as RTC, external memory or I/O extender doesn’t need a long distance for communication. Here the slave and master can be placed closely on those applications.

        But when we are going to use special functions ( interfacing with AFE, Motor driver IC and etc.), we have to carry our I2C signals for the long distance. Because of our master communicate with slave remotely, not a board itself.

        Here I have attached one of my sample schematic diagram .I have tested this circuit one of my application. I have used P82B715 (TI manufacture).This IC can communicate up to 50 meters without any data losses.

      For a very long distance communication, you can use following formula (figure (a)) to find out pull resistor values otherwise go through their manufacture datasheet. But anyway 4k7 and 470R suitable for most of the applications (figure(b))

figure(a)

                                                  figure(b)