Hi Kevin,
The control voltages biased the internal series and shunt FETs, therefore the voltage level will determine the RF performances and power handling of the HMC536. We recommend a tight tolerance on the control voltage input level for minimal performance variation.
The HMC536 can support high state Vctl between 3Vdc to 5Vdc; with better power handling performances (power compression and IIP3) at higher Vctl level. There is minimal change on small signal performances vs. Vdd. I've attached the P0.1/1dB comparison data at 3V and 5V operation for your reference.
Best Regards,
MN