Q
Can I connect the AD711 pin number 8 ( which is NC) to ground
A
The AD711 was designed back East in MA, and I am in CA, so it will take me some time to track down the correct bonding diagram. Some general comments on "NC". _MOST_ of the time, semiconductor manufacturers use NC to mean "no connection inside the package". But be careful, some of them, on some parts, use NC, rather than DNC, meaning "do not connect, there is something inside connected to this pin". Especially on references, you may have three NC pins which are zener-zap pins, and there are bond wires on these pins. For the super precision references, there is a small shift in output voltage due to package stress during assembly, so we zener-zap trim after assembly. The safest course of action is to never connect anything to an NC pin. However, with smaller and smaller packages, a customer may want to route a pc board trace under the package, so they go through the NC pad. A really good engineer will always ask the manufacturer before doing this, so I congratulate your customer for being such a good engineer.