I have two LMX2487E evaluation boards. In both instances I have replaced the on board VCO (4300MHz something) with CRO3412A VCO from Zcomm. The first one worked, but produces transient spikes some times, more importantly, it works with 5V Vcc, which is what the VCO is rated for.
The new one does not lock with 5V Vcc, yesterday I had to increase the voltage to about 6.1 V before it would lock. And then this morning, 7.1, and then this afternoon 7.3. Once it is locked it seems to work very nicely, but the necessary voltage to the VCO is increasing. Is something damaged?
Can I purchase a new LMX2487E eval board without the 4.3 GHz VCO on it?