hmc749 CN port

My HMC749 development board seems to be burnt out during use and it cannot work normally. When I was plugging in the power, I used an oscilloscope to detect the voltage at the CN terminal, and found that the value was 0V, and the CP terminal was normally 3.3V. What is the problem? Is there any way to remedy the problem?

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    •  Analog Employees 
    on Aug 28, 2020 8:29 AM 2 months ago


    How much current does it dissipate? RF input output ports' DC voltages are close to 3.3V and if you probed it with a scope dc coupled to gnd, you are forcing the DC bias points of the part from outside. From internal 50ohms referred to 3.3V to scope's ground, a dc current flows in this case. Could you repeat your experiments using DC blocks for all ports?