Electronics > Beginners
10kHz to 2MHz , 0.25mW to 150mW amplifier
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raff5184:
Hi all,

I need the following amplification:

INPUT:
frequency range = 10 kHz - 2MHz
V = 1 V peak-2-peak
I = 1-2 mA peak-2-peak


OUTPUT:
Vo = 12 V peak-2-peak
Io = 80-100 mA
Power = 30 dBm (about 1W)

Does something like this exist that I can buy? Or I can also build one, but what basic component do I need? Would an OpAmp do the trick?
Also, if the bandwidth is too large for the amplification that I need I can split the amplification in 2 (max 3) sub-amplifiers, each covering a sub range of frequencies, this is not an issue.

Thank you

dmills:
ADSL line driver or two plus a transformer or Balun?
Linear or TI spring to mind for some reason.

Regards, Dan.
T3sl4co1l:
FYI, ADSL drivers are apparently really quirky, don't use them outside the range that ADSL needs (even if the specs say or imply they can run over a normal op-amp sort of range).  Maybe okay here.

A modestly fast line-driving-capable op-amp or buffer should do fine here.  Shouldn't have trouble finding one off the shelf. :-+

Possible gotchas: supply voltage range, slew rate, distortion, RMS output, load impedance (resistive? complex? nonlinear?), transient ratings if any, passband flatness, cutoff band slope, etc.

Reminds me of something I breadboarded years ago,



You might want something more powerful than '390x's for output, for which you might use some SOT-89 BJTs instead, which will get you plenty of dissipation into a copper pour, for 1W output.  Or a TO-126 something or other if you prefer THT.

A discrete solution should be a rather extreme measure, for something that ought to be commercially available, so this is just FYI. :)

Tim
Cerebus:
Tim, nine transistors? Two too many surely?

As to the OP's problem, Jim Williams' Linear application note 47 has a couple of handfuls of useful designs that will meet your spec and a lot of relevant tutorial material. Now on Analog's website: http://www.analog.com/media/en/technical-documentation/application-notes/an47fa.pdf.
T3sl4co1l:

--- Quote from: Cerebus on April 17, 2018, 10:33:07 pm ---Tim, nine transistors? Two too many surely?

--- End quote ---

Alas, t'was before 7TL's time (I said it was old). ;D

It could... ehhhh... let's see:
- The one current mirror could be a resistor and transistor, simple enough.  Worse offset, who cares right?
- The diff pair tail could be a resistor.  This impairs common mode range, but that would be acceptable for modest-gain and inverting applications.

Ahh... that feels better 8)

Tim
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