Choosing between Different Capacitance Crystals

[DrMag]

I have a question about choosing which crystal capacitance you use in a design.

Note that this is not a question about choosing the capacitors--that I can do. Rather, I'm working on a design with an MSP430. The MSP430 has user-selectable load capacitance for the attached crystal, and can work with 1, 6, 10, and 12.5 pF crystals without requiring any external capacitors. 6 pF is, apparently, the default.

Is there a reason I would choose one type over the other, aside from what I have on hand? Doing a design from scratch, is there a benefit to one over the other? Judging by the formula for the load capacitors, my intuition says that the larger the required load capacitance the better, because then the stray capacitance (and any variations in it) is less significant. Does that sound right, or are there other reasons that would imply lower capacitances are better to use, if possible?

[tecman]

Higher crystal capacitance can increase the drive requirements, but will be less sensitive to stray capacitance.

paul