Issue link: https://resources.pcb.cadence.com/i/1526746
3. Regions While we can set rules for any of our nets whether by class or group, oftentimes we need yet another set of rules for specific areas of a PCB. For example, look at the traces on the PCB below. Top view of a PCB layout with different regions highlighted and their specific rules listed Definition: Regions are specific areas on the PCB where unique design rules are applied. Application: Use regions when you need to apply different rules to specific areas of the board, regardless of net group, net class, or general rules on the PCB. Let's say the traces found in the green area must not be any thinner than 6 mils (0.1524 mm) to save on costs and because we don't have a particularly dense board. However, the ball grid array (BGA) chip on the PCB (in the red region of the image above) has such fine pitch pins that 6 mil traces are simply too thick to route the pins. So what is the solution? Make the traces thinner in that BGA chip area. In addition, we must set this rule for all layers of the PCB found underneath this BGA device. Those layers would be the top, middle, and bottom conductor (copper) layers of the PCB. Also, we need to allow for tighter spacing in that region as well to avoid violating general spacing and trace width rules for the entire design. Let's look at the benefits of constraint regions. Example: Define a high-density region containing a BGA device with tighter spacing and trace width rules compared to the rest of the board. REGION PHYSICAL CONSTRAINT SET 23. Open the CM in OrCAD X Presto PCB Editor by going to Tools - Constraint Manager. 24. Shown in the image below, go to the Physical Worksheet/section on the left, then select Region - All Layers. 18 www.cadence.com Part 1 of 5