Original question:
what we did to check if ESD diodes (GND/USB-VBUS) at CC really cause problem.
We cut the line between CC and the ESD diodes. With this change we have now several boards running. No Problem at CC.
If we connect at one of this boards the ESD Diode to CC again again Chip/CC Pin destroyed.
We would like to understand this behaviour to have the possibility to add ESD protection if there are ESD Problems during our tests.
Thanks Christoph
Hello Christoph,
A few things could be happening with the diodes. Diodes have a certain amount of leakage current and if their working voltage is different from the expected voltage, they could be pulling too much current which could cause the circuit to fail (explained here: https://www.youtube.com/watch?v=k301-A-rEe8&list=PL7UxqUbRbxBcM-ukMB0hdMW_iqDuvkUbH&index=2). Diodes also have varying levels of leakage capacitance. For USB 2.0, the recommended capacitance is <2.5pF. In order to ensure you have selected the proper diode, follow the steps below:
If you are looking for an integrated ESD protection solution for CC line protection, we recommend the TPD2S300 or the TPD6S300A. If these do not meet your ESD protection needs, check out the System-Level ESD Protection Guide (http://www.ti.com/lit/sg/sszb130c/sszb130c.pdf) for more details.
For more information on how to select ESD protection, check out TI's video: https://www.youtube.com/watch?v=eiK79hCFff0&list=PL7UxqUbRbxBcM-ukMB0hdMW_iqDuvkUbH&index=6
Thanks,
Emma
