5266 - Diamond / Power Calculator: Which option should user select in "Board Selection" (JEDEC/Large/Medium/Small Board) category under Power Calculator - Thermal Profile section?
Solution:
User can select the option based on the details described below:
JEDEC Board (2S2P) – Specifies that a board defined by JEDEC specifications be used. These specifications are based on real boards and measurements conducted in the lab used by Lattice Semiconductor.
For packages < 27.0 mm in length, the buried planes are 74.2 mm x 74.2 mm (3” x 3”).
For packages larger than or equal to 27.0 mm, the buried planes are 99.6 mm x 99.6 mm (4” by 4”).
Small Board – Specifies that a board that is slightly larger than the JEDEC board be used. The board is assumed to be 6” to 8” square. This setting adds the Theta JB value to the board thermal impedance.
Medium Board – Specifies that a medium board is used, one that is assumed to be 8” to 12” square. This setting adds the Theta JB value to the board thermal impedance.
Large Board – Specifies that a large board is used, one that is assumed to be larger than 14” square. This setting adds the Theta JB value to the board thermal impedance.