Max supply voltage on an MMIC is a function of the supply resistor you choose.
Only the output pin itself is limited to 4.5v absolute max for supply voltage with respect to ground,
and that does not include the AC output signal that might be riding on top of it.?
Look at the top left graph on page 8 of the BGA616 datasheet?
showing device supply current vs supply resistor in ohms.
At zero ohms, the BGA616 looks like a zener diode with a knee around 4.0 volts.
Now look at the test circuit in fig 2 on page 6.
They are powering it from a 6v rail through a series 33 ohm resistor.
So the device is sucking (6v-4v)/33 = 60ma.
Table 3 on page 5 says the total device current is 60ma.
Coincidence?
So just think of it as a zener diode, as far as supply voltage goes.
If you want to feed it from 12v, then use a resistor of (12v-4v)/60ma = 133 ohms.
You lose some gain, because that 133 ohms is competing with your 50 ohm load at the output
for the available AC output power.? If that matters, add an inductor in series with the 133 ohms.
If running without the inductor, you are much better off feeding it from 12v than from 6v.
A string of two or three MMIC"s plus the Hans/Allison design for the BS170+IRF510 push-pull driver and final
could make a very nice power amp for the uBitx.
Downsides?
The MMIC's are not as cheap as the 2n3904's, and are not necessarily efficient with power.
The *Bitx* radios are back to basics, trying to do everything they can with npn transistors,
and an MMIC does not quite fit in.
But they are easy to use, and in a 50 ohm environment there is no need for transformers
Jerry, KE7ER?
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On Tue, Aug 21, 2018 at 12:52 PM, MadRadioModder wrote:
WARNING:? Max Vd on that part is 4.5VDC !!!
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