Issue link: https://iconnect007.uberflip.com/i/1519075
88 PCB007 MAGAZINE I APRIL 2024 not mean you cannot design with PMA; it just means you must do it by hand. e process for designing a printed circuit with power mesh can be simplified to eight steps: PMA Design 1. Build a special library for all fine and extra fine pitch geometries that include loca- tions for blind via-in-pads. 2. Create the board stackup in the EDA tool for a four-layer or six-layer PMA. 3. Place all parts at a closer proximity. e critical factor in placing parts is to place the power pins and connections on a grid approximately equal to the power mesh traces' center-to-center distance. 4. Break through all signal and power nets using blind vias-in-SMT pads. 5. Protect all breakthrough vias so that they are not moveable. 6. Route the power traces to all power pins and connections and protect them. Route critical timing and clock lines and protect them, then route the remaining signal nets on one inner layer and only orthogonal routings on the other inner layer. Buried vias are used to transition from one layer to the other. 7. Complete the power mesh traces to fill in missing legs and balance the power mesh over the entire board's surface. Blind vias need to be placed at each intersection of the same power levels (Vcc or Vdd) so that a power mesh results on the two layers that provide current distribution uniformly across the board. Clean up the board to minimize vias and trace length. Diagonal routing is okay now that routing is complete. 8. Expand all power traces (the mesh) until they meet a signal trace or another voltage level trace. is will create the maximum surface area for the power mesh traces and increase the distributed capacitance between power and ground. Fill the outer layers with ground plane and then stitch the ground planes together where possible (Figure 4). Figure 4: Eight-step PCB design process for power mesh boards.