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Hi
Does it can cause oscillation if we have two B-sides of TCA9517s facing the same I2C bus?
Do you have any suggestion if we need design that 3.3V I2C BUS connect to two 1.8V I2C.
Best Regards
Frank
Having two static voltage offset devices connected in parallel can cause oscillations.
Can you place a TCA9509 in place of one of the TCA9517s? A side should be facing the 1.8V and B side should be facing the 3.3V (I assume currently the 3.3V side is where the B sides are connected). Are there any other I2C buffers on the 1.8V side?
-Bobby
Hi Bobby,
Thank you for your suggestions.
Does it have AECQ parts or other solution could meet AECQ?
Regards
Frank
Our only I2C automotive qualified buffer is the TCA9517. We do have a PCA9306 level shifter that is automotive qualified but its not pin to pin and I can't say if it would be a good part to replace the TCA9517 without seeing a block diagram of the I2C system.
-Bobby
Hi Bobby,
As my topology, I have one 3.3V I2C bus that connecting two level shift TCA9517(B-Side) to change level to 1.8V from 3.3V bus level.
If I replace one of TCA9517 to PCA9306. B-side of PCA9306 connect to 3.3V bus from master, A-side connect to 1.8V device.
Is it be workable?
Frank
B side has a ~540mV offset, if the VoL of B from TCA9517 is larger than the ViL of the 1.8V device then it may not recognize it as a low. The PCA9306 is a level shifter so it will not redrive the signal. This may be a problem if I am understanding the set up correctly.
-Bobby