Circuit Board Extension Reduces Crosstalk
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Solution Overview
Problem
Conventional electronic assemblies experience crosstalk phenomena that degrade signal transmission quality due to inductive and capacitive coupling between signal loops.
Innovation Solution
The electronic assembly incorporates a lead frame with a chip pad and inner leads connected to bonding pads, featuring a patterned conductive layer with a first pad, extension portion, and second pad on the circuit board, where the extension portion overlaps with the inner lead's orthogonal projection, reducing crosstalk by altering the signal path and enhancing signal propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circuit board design is used with standard pad layout, then manufacturing is simple, but crosstalk occurs between signal loops degrading signal quality
Solution Approach 1:
The extension portion extends in the longitudinal direction beyond the first pad, creating a three-dimensional spatial arrangement where the extension portion and inner lead overlap when viewed from above. This dimensional extension allows the signal loop area to be reduced by optimizing the current return path, thereby reducing crosstalk between adjacent signal loops while maintaining planar circuit board manufacturing simplicity
Solution Approach 2:
The extension portion acts as an intermediary conductive element between the first pad and the inner lead. It provides an intermediate connection point that allows the signal to return closer to its source, creating a more compact signal loop. This intermediary structure reduces the loop area without requiring changes to the fundamental circuit board layout or manufacturing processes
2Reliability
If the extension portion is added to reduce crosstalk, then signal quality improves, but device complexity increases
Solution Approach 1:
The extension portion is merged with the existing first pad to form a continuous conductive structure. Rather than being a separate component, it is an integrated extension of the pad itself, fabricated using the same lithography and etching processes. This merging approach reduces device complexity by eliminating additional manufacturing steps while achieving crosstalk reduction through the extended geometry
3Ease of manufacture
If conventional pad design is used, then manufacturing process is simple, but inductive and capacitive coupling increases
Solution Approach 1:
The extension portion is strategically positioned only where needed - extending from the first pad in the longitudinal direction to overlap with the inner lead. This localized modification applies the crosstalk reduction technique only to critical signal paths without requiring changes to the entire circuit board design, thereby maintaining manufacturing simplicity while reducing inductive and capacitive coupling at specific problem areas
Data Source
AI summary
A circuit board assembled with an electronic package having a first and a second inner leads is provided. The first inner lead has a first and a second ends. The circuit board includes an insulating layer, a first pad, a second pad, an extension portion, a conductive via, and a ground layer. The first and the second pads are disposed on the insulating layer. The first end of the first inner lead is electrically connected to the second pad. The extension portion disposed on the insulating layer is electrically connected to the first pad and extends to the position under the second end of the first inner lead. The conductive via passing through the insulating layer is electrically connected to the extension portion and under the second end of the first inner lead. The ground layer disposed on the insulating layer is electrically connected to the conductive via.