Set Minimum and Maximum Propagation Delays
In high-speed digital boards, the pins inside a package tend to have propagation delay. That translates to the nets as well. If
we know the package and part information (usually from the IBIS models) we can set these numbers.
1. In the Constraint Manager, go to Electrical > Routing > Min/Max Propagation Delays. Note how some are already set for
the DDR3_CK1N ECSet.
2. We can manually set delays for our ECSet like the DDR3_DATA set if we know the propagation delay on the DDR3 chip
they connect to. Set them as shown below:
a. Min Delay = 15 mm
b. Max Delay = 17 mm
c. Pin Pairs = All Drivers/All Receivers
Note: These propagation delays set us up for length matching later.
19 www.cadence.com
OrCAD X High-Speed Digital Design Guide
