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US 7,022,919 B2Granted
Printed circuit board trace routing method
AssigneeIntel Corporation
InventorsGary A. Brist, Gary B. Long, William O. Alger, Dennis J. Miller
Life of this patent
Estimating the term…
Abstract
An I/O routing pattern method is disclosed, for use with heterogeneous printed circuit boards (PCBs), such as those embedded with a reinforcement material, for example, a fiberglass weave. Traces are routed on the PCB so as to reduce sensitivity to changes in the dielectric constant (Dk), which are brought about by the strands of reinforcement material contained within the PCB laminate. The method minimizes the local variations, such as the Dk, time of flight, and capacitance variations, that are observed with traditional routing methods on heterogeneous PCBs.
Claims14
A system, comprising:
- a printed circuit board comprising a reinforcement material embedded within a resin-based material, wherein the reinforcement material comprises strands arranged in a weave pattern, the strands of the weave pattern having a predetermined distance between any two strands;
- and
- a trace disposed on the printed circuit board, the trace for supplying a signal path between circuits residing on the printed circuit board, the trace comprising a number of mini-traces coupled so as to form a zigzag pattern, wherein one mini-trace of the number of mini-traces is disposed at an angle relative to one of the strands, the angle being selected so that the one mini trace crosses over a desired number of strands, the one mini-trace further having a calculated length defining a residual trace length for the one mini-trace length and selecting the number of mini-traces so that the residual trace length multiplied by the number is approximately an integer value, wherein
- the calculated length, the residual length, and the angle satisfy the following relationship:
- r(L, d, φ):=d/(sin(φ))×fract(L x (sin(φ)/d)),
- where L is the calculated length, d is the predetermined distance, φ is the angle and r is the residual length.
3 more elements
A system, comprising:
- a printed circuit board comprising a reinforcement material embedded within a resin-based material, wherein the reinforcement material comprises strands arranged in a weave pattern, the strands of the weave pattern having a predetermined distance between any two strands;
- and a trace disposed on the printed circuit board, the trace for supplying a signal path between circuits residing on the printed circuit board, the trace comprising a number of mini-traces coupled so as to form a zigzag pattern, one mini-trace of the number of mini-traces having a length, the length being selected so that the one mini trace crosses over a desired number of strands, wherein the number of mini-traces is obtained by calculating a residual trace length for one mini-trace length and selecting the number of mini-traces so that the residual trace length multiplied by the number is approximately an integer value,
- the one mini-trace further having a calculated angle relative to one of the strands of the printed circuit board, wherein calculated angle is based on the length, the predetermined distance between the strands in the printed circuit board, and the desired number of strands, wherein
- the calculated length, the residual length, and the angle satisfy the following relationship:
- r(L, d, φ)=d/(sin φ)) x fract(L x (sin(φ)/d)),
- where, L is the calculated length, d is the predetermined distance, φ is the angle, and r is the residual length.
3 more elements
A method, comprising:
- identifying a distance between two strands of reinforcement material within a printed circuit board;
- specifying an angle between a trace and one of the two strands;
- calculating a length of the trace when the trace is disposed at the specified angle over strands with the identified distance there between, such that a desired integer number of strands is traversed by the trace at the specified angle and the calculated length;
- routing the trace on the printed circuit board at the specified angle in relation to one of the two strands and at the calculated length;
- obtaining a residual trace length for the trace;
- and routing a number of traces on the printed circuit board in a zigzag pattern, wherein the residual trace length times the number of traces is approximately an integer value, wherein,
- the calculated length, and residual length and the angle satisfy the following relationship:
- r(L, d, φ)=d/(sin φ)) x fract(L x (sin(φ)/d)),
- where L is the calculated length, d is the predetermined distance, φ is the angle, and r is the residual length.
6 more elements
A method, comprising:
- identifying a distance between two strands of reinforcement material within a printed circuit board;
- specifying a length of a trace;
- calculating a angle between the trace and one of the two strands for the specified trace length over strands with the identified distance there between, such that a desired integer number of strands is traversed by the length of the trace at calculated angle;
- routing the trace on the printed circuit board at the calculated angle in relation to one of the two strands and at the specified length;
- obtaining a residual trace length for the trace;
- and routing a number of traces on the printed circuit board in a zigzag pattern, wherein the residual trace length times the number of traces is approximately an integer value, wherein,
- the calculated length, residual length and the angle satisfy the following relationship:
- r(L, d, φ)=d/(sin φ)) x fract(L x (sin(φ)/d)),
- where L is the calculated length, d is the predetermined distance, φ is the angle, and r is the residual length.
6 more elements
Dependencies are inferred from the claim text.