Shock&vibration environment for Hittite PLL

Hello,

We are using with HMC840 PLL in Fractional Mode and 100MhZ REF. We experience some issues at vibration&shock even when Reference don't pass through same vibration environment. I see some spurious near carrier and even loss of lock with RF power loss at some situation until I write all the registers again. Please suggest if you have some vibration sensitivity tests?

I experienced that kind of problems in cavity resonator VCO is the same problem I experience now at integrated VCO?