The LMK61E07 is a high performance device. Therefore pay careful attention to device configuration and printed-circuit board (PCB) layout with respect to power consumption. The ground pin needs to be connected to the ground plane of the PCB through three vias or more, as shown in Figure 9-4, to maximize thermal dissipation out of the package.

Equation 4 describes the relationship between the PCB temperature around the LMK61E07 and its junction temperature.

where

• T_B: PCB temperature around the LMK61E07
• T_J: Junction temperature of LMK61E07
• Ψ_JB: Junction-to-board thermal resistance parameter of LMK61E07 (36.7°C/W without airflow)
• P: On-chip power dissipation of LMK61E07

To ensure that the maximum junction temperature of LMK61E07 is below 115°C, it can be calculated that the maximum PCB temperature without airflow should be at 90°C or below when the device is optimized for best performance resulting in maximum on-chip power dissipation of 0.69 W.