[G0HZU_JMR]

I did a few quick measurements of a GALI-51 eval board this evening (when biased at 65mA) to look at how the OIP3 changes when the GALI-51 is driven quite hard.

I got the results I predicted back in post #82 where the OIP3 degrades at very high output levels. It looks like the 35dBm figure only applies when the output level of each test tone from the GALI-51 is below about +3dBm. If each output tone seen on the analyser is at +10dBm the OIP3 degrades to about +32dBm and with GALI-51 output tone levels each of +13dBm the OIP3 degrades to about +25dBm.

My spectrum analyser is quite old now but it does have a built in OIP3 measurement function so it helps speed up the whole process. I used 60dB internal attenuation for the highest output levels and I also checked the result using an external attenuator. The distortion performance below is definitely that of the GALI-51 and not the analyser. This may explain why you only saw an OIP3 of +30dBm with some of your tests. You may have been driving it quite hard.

All of the tone levels are measured at the output of the GALI-51 as seen on the spectrum analyser.

o/p tone levels OIP3

13dBm 25.1 dBm
12dBm 28.2 dBm
11dBm 30.8 dBm
10dBm 32.3 dBm
9dBm 33 dBm
8dBm 33.4 dBm
7dBm 33.6 dBm
6dBm 33.9 dBm
5dBm 34.1 dBm
4dBm 34.4 dBm
3dBm 34.6 dBm
0dBm 34.9 dBm
-10dBm 35.1 dBm