Placing Analog Macros

In my design I am having ADC, DAC and memory blocks. Since the chip deals with both analog and digital signals, what care should I take while placing these macros and in subsequent stages of the PnR flow?

for analog you usually have lots of power concerns and interaction concerns (such as guard rings). it is likely that the analog blocks do not use the same power source of the digital parts and floorplan has to especially take that into account. analog usually requires pads that are specific for analog, and you will most likely want to place the analog block as close to its IOs as possible. analog pads, in general, cannot live on the same pad ring as the digital pads.

for the remainder of the flow, you might have to do some special treatment for the analog pins that connect to the digital logic. sometimes there are false paths that you have to specify by hand, sometimes the load on the pin can only be a certain value, etc. you need to work very closely with the analog designer to make sure you are not 'killing' his block with your assumptions.