My customer will use HMC962LC4E in their system and test the performance of HMC962LC4E now.
And during the test with HMC962LC4E , they say that they got some probelems.
Please refer below questions and let me know your answers ASAP.
1. Test Enviroment
They use parameters only in attached schematic and PCB gerber file.
And they use below test equipments in this test.
* NA: Keysight N5230A
* SG: Keysight E8247C
* SA: Keysight N9030A
* Power: Linear Power Supply
1) Gain turn around phenomenon
Would you confirm below phenomenon is right things or not?
They say that Gain value is rising at almost 0 dBm of input power and over 15GHz Freq. Band.
For this, they worry that this phenomenon is caused by oscilation.
So they need your confirmation about this phenomenon .
Please confirm above thing.
2) Oscilation phenomenon
During their test, they got CW as oscilation in 20.5GHz BW.
This phenomenon is often occurred at NA, and rarely occurred at SA.
It seems to be sensitively oscilated at S11 & S22.
Woudl you advise how to avoid this oscilation?
In other words, would you suggest them your recommended circuit diagram except diagram in datasheet?
They will try to do this test again with your recommended circuit diagram.
Please advise me ASAP.
If you have any questions, please let me know.
Thanks for the additional info.
This kind of instabilities general occur due to damaged part or poor pcb layout. The current values looks ok, so the device may not be damaged.
The layout connections…
HMC962LC4 does not have an oscillation history that I am aware of. These kind of instability behaviors most probably occur due to the PCB layout or the end launch effects. At first sight…
Please refer below answers from my customer.
What are the measured Vdd and Idd values for HMC962LC4 pins not the resistors, with no RF, -20 dBm and at Psat?
* Vdd: 3.33V @Vdd port. / Idd: about 80mA w/o RF input.
* Vdd: 3.30V @Vdd port. / Idd: about 80mA RF input power -20dBm.
Could you share spectrum analyzer screens showing the oscillation shape?
Please refer to the attached file. (20161012_175801.jpg)
Does the oscillation shape change with input power level and Vdd?
No. it is not changed the shape of oscillation as input power and Vdd.
Could you share the layout with GND vias under the package is visible?
Please refer to the attached file. (HMC962 _Bottom VIA.pptx)
Do you have an ADI EVB that you can install the same device and test with ADI EVB? –
No, I don’t have.