HMC408 has no ground pins and the package base has to be connected to ground. Since this device has several N/C pins,
I am wondering if those pins do not have kind of internal connection and I could connect them to the exposed metal ground.
As far as I see on the gerbers of the evaluation board, it seems that some of them are used this way (pins 2,4,6,8,12,13 and 15). Is that correct? Could I use those pins to make more easy the connectios to ground? Why not pins 5 and 7?