One of my customer made his prototype board with HMC802 mounted.
Three HMC802s are located at output terminal of his prototype and are connected in series.
He made 4 boards of prototype and 2 boards has problem.
The problem is very low impedance between Vdd and GND of HMC802 device with around 2ohm to 10 ohms impedance.
The 2 prototype boards now failed was working okay when he first tested.
Some day later, 2 boards has the trouble as mentioned above.
The symptoms are all the same, very low impedance between Vdd and GND.
He once made test with VSWR meter connected to the output terminal of his board. During his VSWR test, power of his prototype boards was not turned on.
RF power from VSWR meter was around 0dBm.
Could you suggest us what might cause the failure?
If you have any advice to allocate the cause of the problem, please let us know.
In his board, Vdd is +5V, V1 is 0V or 3.3V from FPGA.
He will use HMC802A for his production unit when the problem is resolved.
Do all 3 HMC802 devices on a single board fail? Do all 4 prototype boards fail now?
HMC802 devices could be damaged due to some kind of EOS event:
Are there DC blocking capacitors at RF input and outputs? An application circuit would be helpful.
Is the control voltage applied after supply is powered up?
We don't recommend to apply RF signal before supply is power up but the HMC802 should be safe at small RF input levels like 0 dBm.
Thank you for your response.
He built 4 prototype boards.
One board, all 3 HMC802 devices failed, and another one board, just one HMC802 failed.
Other 2 boards are working OK.
The DC blocking capacitors are connected at input and output as shown in the data sheet, customer mentioned.
Whether the RF signal application before supply is power up or not, I will confirm to my customer.
Thank you again for your comments,