allowed input RF polwer level in downconverting mixer

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yefj

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Hello I want to use the following mixer as down convernter.
I am intrested regaring the allowed power levels that could be used.
according to the datasheet the reccomended LO power level is 13dBm.
I read in the internet the RF needs to be 10dbm lower then LO power level.(13-10=3dBm RF input)
1dB compression point of 9dBm means I can use this RF input up to 9 dBm?
What is the allowed RF level?
1736849380051.png
 

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Don't expect meaningful results above specified compression point. Datasheet has also maximum rating of 50 mW (17 dBm).
 

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To maintain linearity in the mixing process and prevent intermodulation distortion, in a diode mixer, the RF input level should be about 10dB lower than the LO input level (or even lower). In this case, above +9dBm (P1dB), linearity issues, intermodulation distortion, and harmonics, become a certainty.
 

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Hello, I am using this mixer as down converter. So if they say P1dB 9dBm then the RF input at this compression point is 15dBm
9+7=15dBm. So at RF input 10dBm we are not going to be compressed
But then we have a situation when LO power is larger then RF power only by 3dBm (in contrast to the rule that LO=RF+10dBm)
Thanks.

1736944836702.png
 
Last edited:

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You are wrong in your assumption. If is written that the compression point P1dB (at RF input) is +9dBm, means THAT is the point where the compression starts.
Any other calculations are meaningless.
I think that 50mW (+17dBm) is the maximum accepted input power. Minicircuit's datasheet is not very clear in this regards. Their datasheet lacks "maximum ratings".
 

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P1dB is input ? Not output ?
I am confused .
Because I know that compression is a measure of output .
Thanks .
 

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P1dB it is the input power level at which the output power of the amplifier begins to compress and deviate by 1dB from the ideal linear relationship between input and output.
If refer to the gain of the amplifier, P1dB is the output power level at which the gain decreases 1dB from its constant value.
 

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yefj said:
P1dB is input ? Not output ?
I am confused .
Because I know that compression is a measure of output .
Click to expand...
For a mixer only input power makes sense for 1dB compression spec. There is more than one output frequency; which one do you measure or do you measure both?
 

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So for a mixer P1dB is the input value (RF) which makes the output(IF) compressed.
And in amplifier P1dB is the opposite?
Thanks.
 

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P1dB refer to either input or output (often specified as OP1dB or IP1dB). This is the case with any device (amplifiers, mixers, whatever). That datasheet doesn't specify which port it's referring to, but it only makes sense referring to the input port.
 

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Why it makes sense as an input in this mixer case?
Thanks.
 

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yefj said:
Why it makes sense as an input in this mixer case?
Click to expand...
Look at the loss plot you posted above, if the 1dB CPG was at the output, the input would be somewhere between +16 & +18dBm which for a mixer with a nominal +17dBm LO makes no sense.
 

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