Issue link: https://resources.pcb.cadence.com/i/1532919
Teardrops (Fillets) Purpose: Ease the stress on copper traces and pads, especially for signal integrity and flex PCBs. Steps: 1. Open the Constraint Manager and go to the worksheet in Manufacturing > Design for Fabrication > DFF Constraint Set > Copper Features. 2. Then you can see a constraint set (or create one similar to previous methods). 3. Under the Flex section, you have options for turning on the checks for Missing pad fillets and Missing T fillets and Missing trace tapers (see below). 4. Apply the constraint set by clicking the Design > Copper Features worksheet below. 5. Then you will already have the DFFCFCS1 constraint set applied to your Conductor layer (or you can apply it), and the values for the fillets will populate if you have any to add. If any fillets (Teardrops) are missing, especially for flex PCBs, you know where to add them because the DRC tool flags an error if they're missing. Impact: More reliable pads and traces, less breakage and damage on regular and flex PCBs after bending, and improved signal integrity by reducing the abrupt change in characteristic impedance. Pad To Mounting Hole Spacing: Minimum Distance Between Pads and Mounting Holes Purpose: You want to avoid placing traces to mounting holes to avoid unintended shorts. Mounting holes often have metal bolts/screws used to mount the PCB which may or may not be connected to ground or some signal or power. By ensuring the mounting holes are far enough away from your traces and pads, you reduce the chance of unintended shorts and a smoking PCB. We won't explore the entire procedure but will just highlight where to find the constraint set option and where it can be applied. 31 www.cadence.com OrCAD X Constraint Management Guide