The table shown here is an example of thermal resistance parameters typically found in ROHM datasheets. They show the θJA (Theta J-A) and ΨJT (Psi J-T) numbers for different package configurations. The units are degrees-Celsius per Watts. The thermal resistance number is shown for both 1s (single-layer PCB) and 2s2p (four-layer PCB) following JEDEC specifications. The specification of the different PCB boards used to take the data is also on the lower half of the table list. The picture on the right depicts the different PCB board setup for surface-mount or through-hole packages.