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