[time-nuts] Buffer amplifier, OP Amp, vs MMIC, vs discrete?

[Bob kb8tq]

Hi

With many (but not all) of the MMIC’s the phase noise / ADEV degrades more than a 
bit as you drive them near their “rated” output. Since you don’t *need* a lot of gain in
a distribution amp, their high(er) gain is of no benefit. If you pad them on the input, 
noise figure degrades. If you pad them (say by 10 or 20 db) on the output, you burn 
a lot of power in that pad. 

That’s the short list … there are a few other issues as well.

Bob

> On Apr 3, 2020, at 6:07 PM, Taka Kamiya via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> I'm seeing a fairly obvious trend on this list.  When it comes to buffer amplifiers, many people, in fact, most I've seen recommends fast OP Amp.  Discrete Amp, such as ones from K5FX design, NIST design, Clifton amp, and others are mentioned only sometimes.  Trends are similar for distribution amps.  Video amps are generally not recommended.
> 
> But I have never seen a suggestion of MMIC like ones from Mini-circuits.  There are few that work from DC, fairly good NF, but often too high of gain.  Other than high gain, are there reason NOT to use MMIC?
> 
> --------------------------------------- 
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
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