P82B96: I2C over long distance

Pavel Yermolenko

Part Number: P82B96

Hello,

In the P82B96 datasheet (on the 1st page) there is diagram showng the I2C connecting over a twisted pair.

In this diagram SCL "twisted" with 12V, SDA - with GND.

From this diagram it is not clear if the 12V on the "slave" board is supplied by the master board (over a twisted pair line)...or if there is 12V on either side and 2 power sources are "shorted"?

Thanks.

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 317480 points

This example assumes that the remote board is powered through the cable. But this is not required; you could use two separate supplies, as long as they share a common ground. (Small differences do not matter; the inputs are overvoltage tolerant.)

+1 Tyler Townsend over 2 years ago

TI__Mastermind 49548 points

Hi Pavel,

Like Clemens stated already, there can exist two power supplies or the remote device can be powered by the 12V supply to the main P82B96. Either is fine, because the cabling between the two P82B96 is long for I2C standard, but not long enough to where large ground potential differences exist.

Regards,

Tyler

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P82B96: I2C over long distance