Quote:
Originally Posted by Bazz4CQJ
Out of my depth now; could you explain the significance on the number of holes around the MMIC?
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You don't just have to lay out a circuit board to be good at the frequency you intend using it at, you also have to use layout techniques good across the entire frequency range your active devices have gain at. The range of frequencies you don't want it to oscillate at is much wider than what you plan to use it at.
These MMIC amps are small and cheap and simple looking, but they have gain at frequencies where plated stitch holes in a printed circuit board used as connections to the ground plane look inductive enough to foster oscillation. So you need to parallel up a load of stitches and use ones of a suitable size to get good enough grounding to keep the little beggers stable.
You get the same trouble with microwave band transistors.
David