Is it OK to share a LT3045 Vout power rail across the Vdd input of multiple HMC8412 devices ?

Answer: The following configuration shown should work well. The LT3045, with a maximum output current of about 500 mA, is adequate. Each HMC8412 draws roughly 80 mA at saturation (around 160 mA total for two), per the datasheet’s power‑sweep data. Adding ferrite beads to both rails will isolate the LNAs and, in combination with the VDD bypass capacitors, form an effective low‑pass filter.

What is the maximum RF input power (Pin) that the HMC8412 can handle with and without DC bias?

Answer: The maximum RF input power for HMC8412 when unbiased and with no Vdd connected (i.e. just RF input ) is less than +7 dBm. In addition, that HMC8412 can survive +20 dBm input power with 0V DC bias and Vdd present . The part remains functional up to +25 dBm, specified max input power in normal operation when DC bias is present.