6. The Constraint Manager shows what the total etch length of the traces are in real-time, including the length of the
unrouted parts and even the percent of the routed net over the Manhattan distance (orthogonal position and distance if
only routing at 90-degree angles).
Impact: Manufacturers have significantly reduced the rise times of chip signal transmissions, and we may not always have
enough space on a PCB to slow these signals down. Fortunately, we can shorten trace lengths, which helps create a more
compact PCB layout. This reduction minimizes the chances of signal reflections, preserving signal integrity and ensuring
effective communication between devices for optimal PCB functionality. It's essential to set maximum trace lengths to avoid
critical timing issues and signal degradation, especially for high-speed signals, as longer traces can lead to increased
attenuation and skew.
Length Matching
Purpose: Ensuring that traces carrying related signals are of equal length. Matching the lengths of data lines in a memory
interface to ensure synchronized data transfer.
Diagram showing matched-length traces on a PCB.
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OrCAD X High-Speed Digital Design Guide
