Vishwanath,
in order to discuss this topic, it is important to know whether your design is integrated on a high- or low-resistivity substrate. Simply check whether you are using an epi process or not.
Maybe you could also mention the operating frequencies of digital and analog part, as well as the sensitivity of analog (high-resolution converter and RF vs. low-resolution blocks).
In the meantime, you can already have a look at the following document:
http://www.specctra.de/whitepapers/sca443.pdfPaul