# Will this RF power transistor work for RF power amp at 2.4 GHz?

#### skatefast08

##### Full Member level 3
I am considering using MWT-173 as a power transistor for a 2.4 GHz < 1W power amplifier. Do you think this transistor will work for my application, if not why and what transistor would you use instead? I'm trying to get transistor to be as cheap as possible and be in my range.

Thanks,

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#### KlausST

##### Super Moderator
Staff member
Hi,

But I assume it depends on the circuit. More detailed:
* schematic
* input impedance
* output impedance
* expected gain
* supply voltage
* expected distortion
....

Klaus

#### vfone

MWT-173 is a low power MESFET designed to be an LNA (low noise amplifier).
Its gain at 2.4GHz is about 13dB, and for a max DC power consumption of 300mW I expect the output power using WiFi modulation to be less than 150mW.

### skatefast08

points: 2

#### skatefast08

##### Full Member level 3
So, I should be able to get 150mW of RF output power?

#### BigBoss

So, I should be able to get 150mW of RF output power?
It's intended to realize an LNA not PA.This is a very expensive transistor and doesn't make sense to pay 25 Euros to get 150mW only.
There are many alternatives which will serve for more power..

#### skatefast08

##### Full Member level 3
It's intended to realize an LNA not PA.This is a very expensive transistor and doesn't make sense to pay 25 Euros to get 150mW only.
There are many alternatives which will serve for more power..
Can you show me an example of a transistor that is cheaper and can supply more power output than the one I mentioned? Every RF power transistor that can work at 2.4 GHz I found, is no less than $15. #### ge ##### Full Member level 4 What kind of power are you looking for Skatefast08? Do you have power or thermal considerations? #### vfone ##### Advanced Member level 5 #### skatefast08 ##### Full Member level 3 What kind of power are you looking for Skatefast08? Do you have power or thermal considerations? Well, Idky I would care so much about thermal, if all I want is my PA to be more powerful? Is it cause of longevity or? Of course I don't want my transistor to fry though. I would like my PA to work for at least 10 years. Last edited: #### BigBoss ##### Advanced Member level 5 Can you show me an example of a transistor that is cheaper and can supply more power output than the one I mentioned? Every RF power transistor that can work at 2.4 GHz I found, is no less than$15.
I have found this in few minutes.You can find another cheaper and more convenient..

skatefast08

### skatefast08

points: 2

#### skatefast08

##### Full Member level 3
Would this transistor need a heat sink? I don't want my circuit to be so bulky and all I need is no more than 100 mW, I think? I want a receiver to pick up signal from no more than 200 yards. If my phone or computer can pick up a signal from that distance, which I know it can, I have tested it, then what kind of power amplifier transistor is being used? Putting a heat sink on the RF power amp would make your computer or phone very bulky. I want to design off chip rfic design at 2.4 GHz about 100 mW output power and the size of the rfic to be no bigger than about 3x3 inches and regular thickness of a pcb board.

#### ge

##### Full Member level 4
Skatefast, I'd recommend a MMIC, not discrete if size is important. At 20dBm, VPhone has a number of good suggestions (MiniCircuits & NXP).
Cheep, easy. Solder it down and move on.

#### skatefast08

##### Full Member level 3
Skatefast, I'd recommend a MMIC, not discrete if size is important. At 20dBm, VPhone has a number of good suggestions (MiniCircuits & NXP).
Cheep, easy. Solder it down and move on.
Size can be anything from 3x3 to like 5x5 inches at the most. I am trying to exclude anything that is on-chip. I want my design off chip. A MMIC wouldn't be relevant to my design.

Couldn't I essentially use the MWT-173 to get 100 mW of output power by using transistor used for designing LNA also?

Thanks

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#### BigBoss

Size can be anything from 3x3 to like 5x5 inches at the most. I am trying to exclude anything that is on-chip. I want my design off chip. A MMIC wouldn't be relevant to my design.

Couldn't I essentially use the MWT-173 to get 100 mW of output power? Then I could use a transistor used for designing an LNA also?

Thanks
This one is appropriate..

skatefast08

### skatefast08

points: 2

#### ge

##### Full Member level 4
What is "on-chip" vs "off-chip"?
BigBoss has a fair suggestion in the BFQ790. Infineon has good data on the part for matching. It should be relatively easy to match.
I see the MWT-173 in stock at Digikey but no where else. Also, I see only a datasheet on the MWT-1 (unpackaged version).
I'm lazy. I see the PMA4-33GLN by MiniCircuits as cheep and easy. The BFQ790 will be more efficient.

#### skatefast08

##### Full Member level 3
BFQ790 is not a transistor. I want to work with a transistor, not an RF power amplifier that is already created.

#### JohnBG

##### Junior Member level 3
if BFQ790 fits and delivers, why do you want a transistor? on same line, why not 2 balanced transistors? doherty configuration?