Issue link: https://resources.pcb.cadence.com/i/1526746
EXAMPLE - CREATING A NET CLASS Here's the real benefit of using net classes. Let's say you know you need 2 Amperes going through any of the power traces in a design (VDD_5V_USB, VDD_3V3_EDP, and so on) at any given time. We know that a 10 mil (0.254 mm) trace with 1 oz copper can withstand a 1 amp current at a 10°C temperature rise, so we decide on 10 mils for each of our power traces or a range of about 4 - 100 mils (0.1 - 2.540 mm). We have the option to set a rule to each trace width, but instead, we can set a rule to a class instead, then put those traces into that class, and have the 10 mil (0.254 mm) width rule applied to all of them at once. This is the power of Net classes. To demonstrate this, let's Group all power nets into a "Power" net class in the CM. In OrCAD X Presto PCB Editor, open the CM using by clicking Tools - Constraint Management. The CM will appear as shown below. 1. Go to the Physical Constraints Group (where we will set physical class definition for physical properties we want in our traces) 2. Under the Nets section, select All Layers from the dropdown item. 3. The spreadsheet will open up. 4. Select the cell that says VDD_3V3_EDP. 5. Hold the Shift Key. 6. Select the VDD_5VD_HDMI_CON cell. All the selected cells will be highlighted among them in blue. 7. On any of the selected blue cells, right-click to generate a pop up window. 9 www.cadence.com Part 1 of 5