900MHz VCO

The circuit has the purpose of testing the performance of the MAX2623 900 MHz VCO.  A multiturn pot tunes the varicaps and hence the frequency; for experimental purposes an FM modulatin signal can be injected via a .1 capacitor; the buffer output, internally connected to a dc blocking cap, is injected into an MMIC amplifier.

There is a mistake in the schematic: the .1 and 220pf capacitors must be connected in parallel between ground and the 100K/upper potentiometer lead node.