MMZ09332B NXP power amplifier

[guytoub]

hello, I have a little problem understanding the datasheet for this component.they talk about small signal gain equal to 24dB @900mhz while on the S parameter file provided, the gain is 13dB. why this difference?

https://www.nxp.com/docs/en/data-sheet/MMZ09332B.pdf

 

[BigBoss]

Do you know the difference between "Power Gain" and "S₂₁ ?

More information

Calculate power gain from two-port S-parameters - MATLAB powergain

This MATLAB function calculates the transducer power gain of the 2-port network by:...

www.mathworks.com

 

[guytoub]

I am self-taught in the field and I don't know everything. can you explain to me very simply how to understand this and how to interpret it on the datasheet please

 

[G4BCH]

S-parameters are measured with the device with a 50 ohm source and load. The data sheet gives the performance with matching circuits between the device and 50 ohms, hence the increased gain.

 

[D.A.(Tony)Stewart]

Did you use 13 db using 10 * log (s21) is power gain from s-parms?

Does NXP use voltage gain or power gain for s21 (dB) ?

If I assume NXP's file for s21 is voltage gain then I used 20*log (s21)

- old ref on discussing this...

Is S21 a voltage gain or power gain ??

Hi all, This question might be too easy for you :P But, I am so confusing, since from the definition of S parameter, it is defined as a ratio of voltage (or current) signal. So, it should be a voltage gain. However, I have seen in several papers mentioning it as a power gain ??? How come ...

www.edaboard.com

 

[volker@muehlhaus]

S-parameters are measured with the device with a 50 ohm source and load. The data sheet gives the performance with matching circuits between the device and 50 ohms, hence the increased gain.

Exactly. From the 50 Ohm S-parameters we can see that the "raw" transistor is poorly matched to 50 Ohm.
We really need additional matching network to get the maximum available gain.

"Raw" S-parameters in 50 Ohm environment, with no matching circuit:

Maximum available gain when matched:

 

[guytoub]

this would therefore mean that the S parameter file was measured directly on the pins of the component and in the datasheet we have the S parameter measurements with a matching circuit according to the frequencies used? is it correct?
what is confusing for me is how to interpret these two curves in the attachment. nxp not giving their measurement condition.
I put my component on a layout and I measured with a VNA and I got the same results as their S parameter file

 

[volker@muehlhaus]

this would therefore mean that the S parameter file was measured directly on the pins of the component and in the datasheet we have the S parameter measurements with a matching circuit according to the frequencies used? is it correct?

Yes, correct.

what is confusing for me is how to interpret these two curves in the attachment. nxp not giving their measurement condition.

The second curve that you show is for a matched amplifier. In the data sheet the circuit and layout are shown together with that curve.

 

[guytoub]

thanks you very much guys for your help .
everything is clear for me now .

 

[biff44]

i do not see this S-parameter file in the OP post, so i can not discuss in detail.
but you do realize that S parameters of a semiconductor device are UNMATCHED. i.e. you take the semiconductor chip, and measure the input and output ports on a 50 ohm network analyzer.

so if the Sparameters say X gain in a 50 ohm system, and then you ADD an input matching network and an output matching network, you can reduce the input and output return losses, and that will make the apparent gain be much higher.