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40 I-CONNECT007 MAGAZINE I JANUARY 2026 Example: Our case study uses a 0.00512" wide × 0.00137" (1 ounce) thick inner-layer trace carrying 2 amps. • IPC-2221 internal chart predicts: ΔT = 937°C • IPC-2152 predicts: ΔT = 80°C • Case Study maximum: ΔT = 11°C The IPC numbers are not errors. They represent results from the original experimental data used to create the design charts in those standards. In the real 8-layer board, copper acts as a heat spreader, drastically lowering trace temperatures. TSDC Solution: Grid-Based Effective Thermal Properties This example problem uses Solaria PCB thermal analysis software (Harley Thermal LLC) to: • Import ODB++ from your CAD tool • Divide the board into any 3D grid (e.g., 9 × 9 × 1 = 81 nodes, can be any grid size) • Calculate effective thermal conductivity (keff) in X, Y, Z for each node • Extract minimum and maximum keff values bounding the thermal performance • Run IPC-TM-650 2.5.4.1a thermal simulations to generate custom current, cross-sectional area and ΔT charts a. IPC-TM-650 2.5.4.1a, Conductor Tempera- ture Rise Due to Current Changes in Con- ductors. This is the IPC Test Method fol- lowed to create the charts in IPC-2152 and in IPC-2221. Figure 2 shows a one-ounce test trace carrying 2 amps routed across areas of the board that have varying amounts of copper. Figure 3 reveals the steady-state temperature variation along the trace length and a maximum trace temperature of 36°C. Example PCB Information: 8-Layer FR-4 Board Board specs: • Size: 6" × 8" × 0.071" • Material: FR-4 • Layers: 8 (1-ounce copper) Figure 4 shows the example PCB layout. Figure 5 illustrates the 9 × 9 × 1 grid pattern. Figure 5: Grid divides board into 81 nodes for K eff calculation (left). Keff normalized (right) red = highest copper content, white = lowest. Figure 2: a) PCB layers imported into Solaria PCB; b) 2-amp trace on an inner layer. Figure 3: Maximum and minimum temp rise 11°C (low copper area) to 7°C (high copper) with the same boundary conditions as IPC-2152. Figure 4: 8-layer FR-4 board used for analysis. Inset: layer stackup.