Re: Wow... 15 volts in and a bunch out..
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If they're similar to MARS MMIC, input and output MUST be 50 ohms.
73
Ken VA3ABN
On Tue, Aug 21, 2018 at 3:52 PM, MadRadioModder <madradiomodder@...> wrote: WARNING:? Max Vd on that part is 4.5VDC !!! ? ? ? So I read the BGA616.? ?$1.50 from Digikey?? ? ? I see you provide a 33 ohm collector load resistor, drive it with 6 volts or less, and it SEEMS to have a 50 ohm input impedance and its own biasing.? ? ? Pretty interesting little amplifier.? ?Supposed to provide a power gain of 20 dB.? ? Seems like more than we really need but extra gain is probably easy to throw away with MORE negative emitter feedback resistance, instead of fighting for every bit we can pull out of 2N-3904 or other transistors.... ? Are there any downsides that you see to adding this after Q90? ? Gordon ?
Oh, I haven't done it.
Just kibitzing.
It could be another npn gain stage, just that an mmic involves fewer parts,
so easier to patch in ugly-style on the bottom ground plane.
An example might be U2 of Farhan's specan:
? ??
L5 is not totally needed, you just lose a little gain if all you have is a resistor between +12v and the output of U2.
The input and output of U2 must be capacitively coupled to adjoining stages.
The input and output of U2 are fixed at 50 ohms.
So basically a 4 pin IC, a resistor, and two AC coupling caps.
The MAV11 is an older MMIC, though certainly viable the manufacturer doesn't sell them at less than quantity 20:
? ??
Beware of ebay clones, they may or may not work for you.
There are hundreds of MMIC's available, at various power levels, gains, noise figures, frequency ranges, packages,? ...
Choosing one at random, take a look at the datasheet for the BGA616,? Mouser pnum? ?726-BGA616H6327XT
? ??
Jerry, KE7ER
On Tue, Aug 21, 2018 at 10:17 AM, Gordon Gibby wrote: Hi Jerry, can you produce a schematic with parts numbers on exactly how to do that? ? I¡¯ve never used one of those components before.? It should be easy to reduce gain in previous day just by simply changing some resistors to higher values in the emitter circuits.¡ª though I haven¡¯t looked at them
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