Hello,We have an application in which we are using a DS90CR217 serializer and a DS90CR218A deserializer to transmit and receive data. This app must be able to operate at two different frequencies, so that sometimes, without turning off the system, we have to switch the Tx clock frequency on the serializer between 30 and 60 MHz.We power down the serializer every time the clock is changed, but do not do that with the deserializer. We would expect that sometimes the deserializer PLL can not lock because the clock changed. However, we have experienced (already twice) that the deserializer chip is dead after operating the system for a while.The question would be: Is it possible that the deserializer stops working because of the change in the transmitter clock? In case it is, why?Or should it be for a totally different reason?Thanks!
Greetings -
Sorry to hear of the trouble report. While changing freq on the fly is not recommended it should not cause the 218 to be damaged. Going from 30MHz clock to zero to 60MHz should not be problematic also. In the application, is the LVDS cable plugged and unplugged? Is there a common ground between the SER and DES? It is more likely an EOS (Electrical Over Stress) event or something else that is damaging the 218A device. We would suggest further tests to determine when the part stops working and then root cause what occured just prior. Also what is the sympton of the 218A post probelm? does it draw current, show errors, zero current, get hot? These could also help debug the problem.
John GoldiDPS APPS / SVA / www.ti.com