A 50W VHF(110 to 150MHz) Amplifier

[msseng]

Hi
I wanna design and fabricate a 50W VHF amplifier, so I have searched a lot of transistors and MOSFETs from some known company such as Philips, ASI, Toshiba, MACOM, Integra, etc. But I couldn't find a suitable one.
Please help me to find that.
In fact my preferred requirements are 50-ohm input/output, easy to set up, reliable and hard to fail!

thanks in advance...

 

[erikl]

Good old 2N3375 or 2N3632 in push-pull configuration with 36V power supply. Don't have a circuit diagram, unfortunately.

 

[msseng]

thank you
But I prefer not to use a push-pull transistors and circuits because of their high power dissipation!
Actually I need class AB, C or D amplifier with efficiency of more that 65%.
Indeed, both of two transistors that you've introduced, have output power of about 13W and its not enough for my application, unless I join at least 5 transistors to achieve my goal!

 

[Borber]

Today BJT are replaced by LDMOS transistors. NXP has full line:

**broken link removed**

Some 20 years ago BLY94 was popular.

 

[msseng]

tanx
As it was said at the first post, I've explored most of the companies who creates the power transistor, but I want your help to choose the best that can support my requirements!

 

[Borber]

You should first present concept of your amplifier.

 

[erikl]

... I prefer not to use a push-pull transistors and circuits because of their high power dissipation!
Actually I need class AB, C or D amplifier with efficiency of more that 65%.

Class AB, C or D amplifiers use push-pull stages! With a class B or C in a bridge connection (yes: 4 transistors) of the a.m. type you could easily achieve the required output power.

Class D amplifier is a totally different category.

 

[FvM]

Class AB, C or D amplifiers use push-pull stages! With a class B or C in a bridge connection (yes: 4 transistors) of the a.m. type you could easily achieve the required output power.

A basic class-C amplifier can use a single transistor, a popular power amplifier topology that's well suited for 50 W. I presume that you are targetting to a CW or FM application, otherwise you'll need a linear amplifier.

 

[msseng]

You should first present concept of your amplifier.

It's mentioned in the first post. I need a 50W power transistor for CW AM modulation in frequency band of 110 to 150MHz.

A basic class-C amplifier can use a single transistor, a popular power amplifier topology that's well suited for 50 W. I presume that you are targetting to a CW or FM application, otherwise you'll need a linear amplifier.

Yes, you're right. I need exactly a transistor for working in CW mode.

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Class AB, C or D amplifiers use push-pull stages! With a class B or C in a bridge connection (yes: 4 transistors) of the a.m. type you could easily achieve the required output power.

Class D amplifier is a totally different category.

Dear, You're right. But I need a transistor that has the push-pull or any other topology by itself and also it doesn't need to design new circuit or new combination!
In that case, most of the time, the transistors are internally matched or needs a small matching circuit at input/output to work.
I know about the amplifiers' class, but now I need a transistor with efficiency of more than 50%.