[SOLVED] Driver amplifier debugging

[shashy.br]

Hi all,

I Used a driver amplifier (RF6886-RFMD ) for my 600 watt power amplifier ( MRFE6VP5600) ,

during testing i found that the driver amplifier was working fine at first power ON,

but ,after consequent testing the driver amplifier stage was generating 31.1 dBm instead of 34 dBm.

also the current consumption (Q current) is higher than the recommended 400mA as per datasheet.

Impedance of the driver amplifier VDD pin changed to 30 ohm from >1Mohm

With out switching on the Gate control pin the drain has to consume 0 current ,but it is consuming 200mA.

the small signal gain of the driver stage has come down to 24dB from 30dB.

The small signal output return loss of driver amplifier stage was -5 dB and input return loss of the next stage power amplifier is also -5dB.

Kindly help me out in debugging what went wrong.8-O

 

[shashy.br]

Hello for those who need the info,

the problem was due to the Poor VSWR withstanding capability of the Driver amplifier 3.5:1 ,

i changed the driver amplifier and its working fine now.