Hello,
My customer is observing some crosstalk between NO pin and NC pin.
They would like to know the root cause and mechanism of this crosstalk.
For details, please refer to the following .pptx file.
tidrive.itg.ti.com/.../659164f2-a3a3-4729-970f-0ee7c4429a57
Best regards,
K.Hirano
Hi Kazuhiko,
Cross talk can be explained via this eq. model shown below:
Cross talk is a frequency dependent event where the input on an off channel is coupled to output/active input of the device through Csd (source to Drain Capacitance).
However the cross talk that is typically seen in this part is shown below:
The difference between the customer application and this test is that this test had all pins terminated with 50 Ohm resistances - with digital inputs like I2C there won't be as much current to "dampen" spikes causes by cross talk - this is why the 100 ohm resistor is working - because this matches more closely resembles the test set up that we test this spec under and this resistor will be able discharge the spikes more efficiently.
The largest factors when looking at cross talk is to have good layout - poor layout of the IC can increase cross talk as well - but I think this is a more so a result that the damping resistor that you have added will work best as it helps smooth out the spikes caused by the pulse on a off channel.
For more information about cross-talk in multiplexers please see our precision labs video on the subject here.
If you have any other questions please let me know!
Best,
Parker Dodson
