1) What is the optimal thermal PCB layout? Does the evaluation board DC2327A represent the optimal thermal PCB layout?
2) The datasheet has several thermal theda values: theda_JCtop = 20.6, theda_JCbottom = 5.1, theda_JB = 6.0, theda_JA = 15.5. Which would I use for analysis of the BGA packaged soldered to the board without a heatsink? I am particularly confused about the difference between theda_JCBottom and theda_JB. I want to take advantage of the theda_JCbottom thermal resistance, but I am unsure what PCB layout and assembly configuration resulted in theda_JCbottom.
1) DC2327 represents a good design.
2) I was able to dig up the archives on this model and found that it was in fact simulated on a detailed and optimized pcb. It appears the JCbot value of 5.1 is a good one. Also, the difference between the JCbot and JB is that the pcb is sinked for JCbot and not sinked for JB.
Great thank you!