Re: 2N2222A vs 2N3904 sourcing


In response to Warren's question about why the MMIC's would be sensitive to oscillating..  

According to the datasheets, they are very sensitive to ground loops.  The datasheet for the HP/Aligent MMIC on the 30dB board available on Amazon was quite clear on this, and recommended using an ultra-thin PCB (0.032 rather than 0.0625) to keep the inductance of the ground vias down where it needed to be to avoid oscillation. 

Given that, it would be very hard to retro-fit one of these MMIC's into an existing board designed for transistors rather than MMIC's and not have it oscillate.


Carl, K0MWC

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