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Pls help me solve PA burn out issue

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ykgbm

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how to solve a burn

anyone:
We have produce a Wlan(11a high power),but often burn out Power amplifier when do power calibration,we doubt it failure by test program issue,someone help see the pirture of PA Datasheet,and tell me know the PA can tolerate out power what it is? thanks a lot,:?::?::?::cry::cry:
 

How are you doing the calibration. I mean share the calibration procedure.
Are you terminating or with out termination the measurement is done?
Because reflections are more in case of no load.
 

Could be oscillating and buring out, possibly operating into a poor load momentarily. Could be your positive power supply comes up before the negative gate supply turns on, and the device draws 10 amps for a short time and fries.
 

Sorry, for everyone, I can't find out root cause in any times,
but i can believe burn out is by terminating or without termination,or the 50ohm load is open status,
 

May I ask once again to share the calibration procedure at various states let say from power on the unit to completion of test that is carried by you.
I mean to ensure that you are not doing any mistake while calibrating.
 

Well, to solve your problem you are going to have to do some tests. Are you set up to do basic rf testing? Did you design the amplifier in quetion, or are you just buying it?

It is likely that it is oscillating, off frequency, during this test. Since oscillations are going to drive the amplifier HEAVILY into compression, there can be big gate currents flowing, which will damage the output device.

You can set up the amplifier with a broadband directional coupler on the output, a 1 dB high power pad, and a moving short circuit. Vary the length of the short circuit, and look at the spectrum analyzer on the coupled (and appropriately attenuated) arm, and see if it breaks into oscillations. Especially look at things like 200 MHz, etc.
 

kspalla:
I have post the logfiles of the calibration test station as attached,pls study it,sometimes the card max power output can be reach 30.5db,it's cause for my douby,
(P.S:when we have do the calibration test,we need additional power(5v) to supply PA,is it calibration procedure require,)Thanks!

Yk
 

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