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JANUARY 2026 I I-CONNECT007 MAGAZINE 41 Results: Custom Charts vs. IPC-2152 Thermal models are made using the minimum K eff (conservative) and maximum K eff (aggressive) ther- mal properties, as the dielectric material in the Solaria PCB models. The minimum K eff is conserva- tive because it represents areas of the board with the least amount of copper. The models are created with the same outline as the original board, although traces are added to the board, similar to the trace pattern in the IPC test method IPC-TM-650 2.5.4.1a. Multiple cases are run to define the data points used to cre- ate design curves for the minimum and maximum effective thermal properties. Figure 8 summarizes the 2-Amp trace analysis and compares the calculated ΔT for each design chart, max K eff , min K eff , IPC-2152, and IPC-2221. Designer Workflow: Recalibrate Early Old rule: Size for 10°C or 20°C rise. New rules: • Use your board's actual keff range from day one to evaluate what temperature rise is best for your technology • Learn what the worst-case stackup and copper content look like from a thermal perspective • Characterize trace patterns or fanouts around high I/O parts; see how moving a trace layer closer to a plane changes the temperature rise • Move forward with more insight to your new designs • Manage the power dissipation and temper- ature rise Learn what the worst-case stackup and copper content look like from a thermal perspective. Char- acterize trace patterns or fanouts around high I/O parts; see how moving a trace layer closer to a plane changes the temperature rise. Move forward with more insight to your new designs. Manage the power dissipation and temperature rise. DESIGN007 Mike Jouppi is founder of Thermal Management LLC. He was the IPC 1-10b task group chair from 1999 to 2016, pub- lishing IPC-2152 in 2009. Figure 6: Min K eff current capacity vs. IPC-2152. Table 1: K eff range tolerances Chart Delta T ( o C) Trace (Sq-mils) Amps % Increase IPC-2152 11 7 0.784 Min K eff 11 7 1.47 88 Max K eff 11 7 2.25 187 % i n c r e a s e = ( N e w v a l u e – I P C - 2 1 5 2 v a l u e ) / I P C - 2 1 5 2 v a l u e * 1 0 0 Figure 8: Trace summary for 2 A, Max ΔT = 7°C to 11°C (Real Design). Figure 7: Max K eff current capacity vs. IPC-2152.