8-Lead LLP Thermal Performance and Design Guidelines Introduction The new leadless leadframe package (LLP) provides significantly increased power dissipation capability in a tiny surface-mount package. The key feature of the LLP is that it has a center metal area located directly below the die which allows a direct path for heat to flow out, providing very low thermal resistance. When this pad is connected to PC board copper to provide heatsinking, values of total thermal resistance (junction-to-ambient) below 40°C/W can be obtained in still air environments. Modelling Assumptions The data listed in this application note is derived from finite element modelling in which the following assumptions are used: 1. DAP (die attach paddle) size = 3.0 mm x 2.2 mm 2. Die size = 2.11 mm x 1.63 mm 3. Package size = 4.0 mm x 4.0 mm x 0.75 mm 4. Power Dissipation = 1W 5. Thermal Vias (0.3 mm diameter) = 8