Analog Discovery 2 Failures

[JaredT]

I am using the network analyzer on the Analog Discovery 2, and have had two separate device failures occur. They have both happened at low frequencies (the start of the bode sweep).   The maximum output voltage is in the range of 2-3V from the source device but a bad connection at the input can cause a transient spike that I presume reaches above the maximum allowed input causing the problem which essentially locks one of the traces at 25Vdc. There is no DC voltage present and the scope probes are AC coupled.

I am reasonably sure that some sort of transient spike is causing this and I occasionally get the “out of range” warning on the first couple of sample of the bode plots. I have installed a pair of 1W 15V zener diodes back to back across both inputs of the BNC connector to prevent any type of transient overload which should prevent any possibility of exceeding the maximum input voltage on a transient basis.

Can you offer any additional insight or confirm that the diodes are the best method of additional overvoltage protection? Any help is greatly appreciated!

Regards,

Jared

[jpeyron]

Hi @JaredT,

This is the correct section for your question. The engineer that typically handles these questions is out of the office for the next few days. I would not expect a response until next week. I am sorry for the inconvenience this may cause.

thank you,

Jon

[JaredT]

Hi @jpeyron,

Thank you for letting me know. That causes no inconvenience and I will happily wait for his response. 

Regards,

Jared

[attila]

Hi @JaredT

In the Network Analyzer AWG output is restarted for each frequency step and this could cause transient behaviour in external circuit.
I don't think you need any diode, just try increasing the Settle time (between AWG start and Scope acquisition) under Network Analyzer, WaveGen, "gear" options.