[Moon-net] ATF54143 project

[Eddy GORA]

Hi all,

How can I estimate actually NF ( can I ? ) of my ATF54143 LNA using audio
techniques. In YO there is no NF equipment as far as I know or some person
to help me with a professionally measure. I setup a simple well known method
for tuning LNA on best NF, measuring S/Z in audio. The TVCR and signal
generator ( capable of 0.032uV @ 50 Ohm, 1Khz modulated with 5KHz dev. ) was
setup in FM mode. Audio measured by Spectran and Spectra Pro. 

I have the following data :

- given NF of TVCR
- minimum discernable signal on TVCR itself, in dBm
- corresponding 1Khz audio modulator tone value, in dB
- same value, but with LNA inserted

I also had some strange problems with ATF's I want to ask opinions. Few
ones, absolutely new, won't work at all ( zero Id, totally burned ) and
others have greater NF, in fact, performed worst than TVCR itself :) I
suspect ESD problems on me but not sure because my bias it's active one (
current mirror like in Agilent app. notes ) and measured Id, Vg was some
kind ok ( much lower than expected ) so transistors had work, but very
badly.

In rest, results was more than expected compared to overall price.

Thanks in advance,
73 Edi, 
   

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