HMC576LC3B's 1, 3, 7, 9 pins and bottom pad are ground. So these pins should be connected PCB's ground. Also It's described in datasheet.
However, evaluation PCB's GND pins don't be connected PCB's ground, like open pins. I'm confused what is the right way.
Anyone help me thank you.
On the HMC576 (as well as the HMC507 which someone also inquired about recently) there are no internal connections to the N/C pins so they can be left floating (soldered to a pad of course) with no impact on RF performance.
Unless there’s a good reason not to do so though (need board space, etc), personally I would ground them so that any noise or stray signal that might find its way to the pin is shunted to ground. There’s probably a very small thermal advantage as well.
I want to purchase the evaluation board
Kindly let me know is it with multiplier die or just evaluation board?