power amplifier design...very much confuse...

hi..i want to design the PA based on this specification:
v = 2v; I= 4.08mA, supplied power = 8.18mW , gain = 22dB; 2 stage PA;f = 2.4 GHZ

can anyone suggest the further step to design that PA...like how to choose a transistor? the design must simulate using ADS

--from that spec..how can i know which class of PA?
--how about the IP3 value/ 1dB compression value???????

How much output power do you want?

Hi,

You need to specify also the P1dB and IP3 requirements your PA need to met...
Refer to good books on PA design:
Microwave Transistor Amplifiers: Analysis and Design from Guillermo Gonzales
RF Power Amplifiers for Wireless Communications from Steve Cripps.

Hope this helps.

RFCMOS

Hi there,
I believe your output power is 31.1dBm, is that correct?
I guess I=4.08mA is the collector quiescent current for stage 1 + 2. From this low value of the current one can say that this would be a class B PA.
You did not specify the PAE, which is the most important spec point of your PA...
The starting point for PA design is usually Load Pull of the final stage. If you use ADS, you will find a good Load Pull project in the example directory.
Mosieur_Oiso

The DC power assumption is 8mW, how to achieve a 31dBm output power?
According to his spec, I guess he want 4dBm output power used for Bluetooth Class 2. Since Bluetooth 2.0 adopted QPSK & 8PSK, so the linearity should be carefully considered, 3~4dB backoff from P1db may be necessary.

Mosieur_Oiso said:

Hi there,
I believe your output power is 31.1dBm, is that correct?
I guess I=4.08mA is the collector quiescent current for stage 1 + 2. From this low value of the current one can say that this would be a class B PA.
You did not specify the PAE, which is the most important spec point of your PA...
The starting point for PA design is usually Load Pull of the final stage. If you use ADS, you will find a good Load Pull project in the example directory.
Mosieur_Oiso

Click to expand...

jariey said:

hi..i want to design the PA based on this specification:
v = 2v; I= 4.08mA, supplied power = 8.18mW , gain = 22dB; 2 stage PA;f = 2.4 GHZ

can anyone suggest the further step to design that PA...like how to choose a transistor? the design must simulate using ADS

--from that spec..how can i know which class of PA?
--how about the IP3 value/ 1dB compression value???????

Click to expand...

Class of PA is decided from your linearity requirement.
If the signal is QPSK or QAM modulated, you'd better use Class AB or A PA for high linearity. If the signal is GFSK modulated, the linearity is not so strigent the you can use Class E of F.

The output P1dB should be larger than your maximum output power requiremet, especially , if you want get a high linearity the P1dB should be designed severals dB larger than your output power reqirement. We call this the power backoff.

Also, you should consider the EVM and spur of the PA, according to the standard.