We are involved in a new design and we would like to use HMC8074 VCO, the datasheet says that only one frequency band must be powered on , but it says nothing about the unsused bands.
Do we have to leave all those pins unconnected or should we connect them to GND?
Thanks in advance.
The supply voltage for unused VCO's should be left floating. Unused RF outputs should be terminated into a 50 ohm resistor to ground.
Is a 'soft' pull-down like 250 ohms acceptable for the unpowered VCO supply lines?
If not, why is it that they should be left floating rather than pulled down?
Also, what is the nominal value of the on-chip VCO power bypass caps?