P82B96: Why is SCL diff pair at TX output referenced to VDD?

Jorge Rive

Part Number: P82B96

I'm investigating the use of this bidirectional buffer in an I2C automotive application, with long cable runs. The datasheet shows the SDA TX data in a twisted pair arrangement with GND, but shows the SCL TX data referenced to VDD. Why is that?

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 324820 points

It is important that the SCL/SDA signals are not paired with each other to prevent noise.

Both GND and VDD are low-impedance signals. You could use two GND lines, one for each, but then you would need an additional line for VDD.

0 Jorge Rive over 4 years ago

Prodigy 200 points

I didn’t relalize power for the buffer on the slave side was being supplied by from master. I get it, thank you.

0 Eric Hackett over 4 years ago in reply to Jorge Rive

TI__Guru 74922 points

Thanks for the help Clemens!

Jorge,

Please let us know if you have any other questions.

Regards,

Eric Hackett

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P82B96: Why is SCL diff pair at TX output referenced to VDD?