Hi Tomohiro-san,
Can you please clarify if your inquiry on the max voltage applied at RF ports are related to the normal signal condition or the possible RF/voltage transient level?
The RF ports of the HMC346G8 are directly connected to the drain/source of the internal FETs, so the dc voltage applied at the ports can possibly affect the electrical performances and as well as the part reliability.
We expect very minimal electrical performance variations for Vrf within 0 +/- 0.2Vdc. The VVA may not be in normal operation when the Vrf is greater than 0.5Vdc or less than -0.5V.
If your inquiry is related to the RF/voltage transient susceptibility level, the internal FET can handle higher voltage for very short pulse RF transient as this will be limited by the breakdown voltage. The HMC346 RF input will be able to handle +15V max for RF/voltage transient with 100s of nano-sec pulse period max.
Best Regards,
MN