I have a setup like this;
PlutoSDR Tx (Freq: 2.45 GHz, Pout: -20 dBm) ------> TSS-53LNB+ LNA (Gain: 19 dB, Pout: -1 dBm) ------> CN0417 (Gain: 21 dB, Pout: 20 dBm)
With this setup, the EVM is around %1.7, without LNA, around %4. So this is why I used LNA to reach -1 dBm Pout. The tx signal is single carrier by the way.
But yesterday I burned my two CN0417s in the test setup. I've measured the CN0417(with beeper), the USB power stage seems OK.
Then I removed the E1 ferrite to disconnect power stage and RF stage. LTM8045 seems OK. I get clear 5V. But the whole RF stage is short circuit to GND.
Then I removed the ADL5606 and measured the PCB again. The RF filter(FL1) and all capacitors are OK except CIN.
Also, ADL5606 is short circuit from RF_IN to RF_OUT between GND (measured after desoldered from PCB).
I do not know how this happens, because I did not exceed the maximum ratings of ADL5606 (maximum Pin: 18 dBm). Even if I exceed, the LTM8045 gives maximum 450mA
and the ADL5606 consumes 540mA to run around 30dBm Pout. So the LTM8045 should not supply this. And maybe should burned because of overload (but seems OK).
Maybe CIN cap burned first then it burned ADL5606 but is a 50V capacitor. I should not be burned easily.
Could you help me to realize why and how this happens?
LNA IC: https://www.minicircuits.com/WebStore/dashboard.html?model=TSS-53LNB%2B
I've reached out to the expert on Pluto about this issue. It appears that what you see is an expected behavior of the AD936x. The calibration process can be disabled but will result to bad…
I have some questions about your setup:
It would be nice if you could attach a picture of your setup as well. It could help us debug the source of the issue.
Thanks for your answer. Regarding your questions my comments are below;
Regarding test setup. I will send a picture of my test setup in a few hours. Just would like to mention that. The LNA board is Nuand BT-200. I've disconnected the FB1 ferrite to disable bias-tee and supply from an external source.
Here is my setup.
Left to right, SA <---- CN0417 <---- TSS-53LNB+ LNA <--- PlutoSDR
Thanks for responding to my questions and for providing the image of your setup. We haven't encountered this issue before so I'm gonna be asking more questions.
I've been trying to recreate your issue today but my setup is without the LNA. My setup is just SMA100A signal generator -> CN0417 -> MXA Signal Analyzer with single tone input signal at 2.45GHz, -1 dBm. I got a gain of 18. I've tried to run the system for more than two hours, the board didn't get busted and was amplifying okay.
Thanks for trying to reproduce the issue. My answers to your questions are below;