LNA cascade

Papabravo

Joined Feb 24, 2006
18,130
So both of the LNAs are powered and the output of one is not overloading the second one. How do you know this?
What is the antenna/feedline impedance?
Output power of the first LNA is 14.5 to 16.5 dBm and you're trying for another 27 dB of gain?
 
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Thread Starter

pulloutyourpoop

Joined Jan 25, 2022
3
yes i am trying to get more gain, how is the output 14.5dbm for first LNA. with a -80 db input signal and 27 db gain, wouldnt the output be -53dbm? Everything is impedance matched 50 ohms. On the datasheet it says the maximum input is ( Input RF Power (no damage) +20 dBm ) so -53dbm is much lower. Unless i am interpreting something incorrectly.
 

Papabravo

Joined Feb 24, 2006
18,130
yes i am trying to get more gain, how is the output 14.5dbm for first LNA. with a -80 db input signal and 27 db gain, wouldnt the output be -53dbm? Everything is impedance matched 50 ohms. On the datasheet it says the maximum input is ( Input RF Power (no damage) +20 dBm ) so -53dbm is much lower. Unless i am interpreting something incorrectly.
I'm just going by the numbers in the datasheet. Tell me, if you interchange the positions of the two devices in series do you get the same result? That is the going antenna to output works and the second one does not?
 
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drjohsmith

Joined Dec 13, 2021
383
A general note,
in case you have not used these thigns before

a) they are extremely static sensitive
b) they are extremely sensitive to having an input with no power applied
c) the input power is defined as the max, not the RMS average,
d) check any DC bias between stages, I don't know these ones, but they might need to be AC coupled
 
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