"Low" Noise Amp

Sep 01, 2017 25 Replies
T

150 ohms, to be exact. I tried that, but got the same noise.

So then is it the transistor, or the cascode? I can't imagine it's the follower...

Tim

Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
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P

I do not understand the need for Q5,6,7,8 - since the input and output are capacitively coupled why the obsessive biasing arrangement. What is wrong with just biasing Q4 via R5?

piglet

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J

And saved a lot of parts!

John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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J

If it doesn't need a lot of signal swing, R5 is all the bias network that it needs.

John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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P

VOM1271? As quiet as it can get and only diodes. ;-)

Best regards, Piotr

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T

Heh.

Well, I need 4mA, so that's kind of out.

Would make it possible to try JFETs though. Use a small coupling cap and a huge bias resistor.

Tim

Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
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