Pashtet wrote on Dec 4th, 2011, 1:46am:Thanks for your sharing.
Both reasons you have mentioned are serios and difficult to simulate. So your general advice is to avoid doing that.
I'm not sure what sriram was talking about, but I agree with Loose Electron. However, I'm sure he'd agree that the extra capacitance isn't a "serious" enough reason to generally
avoid doing it - you just need to make sure you model it and weigh the costs against the advantages because the extra capacitance may (not always) cause more issues than is solved.
Another more practical issue in my experience has been the extra area required. The device needs to be in its own well and the well-to-well spacing is relatively large. This can wind up wasting a lot of space so you have to weigh that (and the capacitance) against the performance improvement.
rg