Question
Please could you advise on the correct process for the pins marked NC on the
HMC832? There is a conflict in the data sheet which states that the pins should
be RF/DC grounded and the evaluation board schematic where the pins are handled
differently, see below.
I would normally expect the data sheet to be correct and it seems to suggest
the better engineering solution, but we should know the reason why the eval
board is wired differently and if there is an important reason for this.
Answer
The NC (no connect) pins have no internal bond wire connection to the die. We
connect signals to various NC pins on our Eval-board simply to help with
routing. For example the Vtune signal on pin 23 is routed through no connect
pins 21 and 22. Customer can either copy the routing from the Eval-board or
just connect all NC pins to ground as recommended by the datasheet.