We are thinking in migrating a current design from HMC767 to avoid excesively low tning voltages to get 8GHz output frequency. Our idea is to use HMC765 instead but phase noise floor degradation seems to be expected. My questions are:
1. it is a real risk on locking HMC767 around such a low tuning voltage (around 1.1Volts to get 8GHz output frequency) or we can go on with original design based on that reference?
2. If move to HMC765, can we take the advantage of auxiliary DC circuitry coming from previous design: HMC976 and HMC860, instead of using those devices recommended at HMC765 datasheet: 3 units of LP5900-3_3V and 2 units of LP3878MR-ADJ (both VCO models seems to have similar current consumption)
3. That 4dB PN degradation from HMC765 higher PN floor is unavoidable to be suffered at 8GHz output (we are going to use PLL as integer with up to 100MHz FPD)
4. Any other recommendation to get the closest possible performance than that obtained previously with HMC767?
A lot of questions... Thanks in advance to help me finding the best possible design at a new frequency.