I have a question about PCB copper planes with buck converters. For reference, I'm using the LM2673/LM2679. The parts are identical in layout, utilizing the DDPAK/TO-263-7 with the PCB tab being connected to the IC's ground pin (pin 4).
Initially, I'm laying out the device on a 2-layer board with the top plane consisting of signal traces only (so you have isolated copper planes on top alongside the traces), and the bottom plane being the ground. However, seeing as how the tab is connected to ground, it seemed more convenient if both planes were ground planes for both the SMT components as well as for thermal dissipation. If I were to use ground pours on both sides, what are some areas which are recommended to keep copper fills out?
EDIT: I found this TI thread that kind of delves into what I'm talking about. I'm using shielded inductors, and based on what it's saying, it seems to promote the idea of removing the top layer copper under the inductor (while keeping the bottom copper filled) in order to avoid EMI issues. So, even though my inductors are shielded, it seems to be better practice if I keep the area of the inductor free from copper. I was wondering if I should apply this practice to other components as well.