11-14-2019 03:15 PM
Please refer to UG576 v1.6 Page 336. Unused TX pins should be left unconnected. In addition, the transmitter should be AC coupled.
11-15-2019 12:00 AM
Thank you for response. I was aware of this recommendation, but we use the GTH as an output external to a unit. So we have the possibilities to ac-couple at both sides Tx and Rx, or only once in the link.
If both sides are ac-coupled a dedicated drain resistor is needed to avoid floating static charging. But this implementaion is not easy to apply at higher data rates.
If only one side is ac-coupled the posibility of short circuit Tx or Rx to GND is a potential risk. Therefore my question, what the consequence is in case of a short circuit.
11-22-2019 02:40 PM
If you have a DC blocking cap between the TX output and GND, there is no issue.