Use of experimental data in guiding thermal specification development

The JEDEC JC15.1 committee is developing specifications for the characterization of the thermal performance of surface mount packages for integrated circuits. This paper documents the experimental data that was used to guide the development of the Theta JA (θ_JA) specification. The goal is to improve the consistency of results that claim to be θ_JA data by tightened specifications for thermal test environments and measurement procedures as well as changes in nomenclature. Under the new JEDEC specifications, θ_JA will not be reported for measurements taken with the surface mount package on a multilayer printed circuit board. Measurement of θ_JA should be done according to JEDEC Standard EIA/JESD51-2 which requires a single layer board in a one cubic foot box under natural convection. This particular specification is only one in a series of specifications; the committee is addressing thermal characterization of packages on multilayer boards, measurements under forced convection conditions, junction to case characterization, and other specifications