Leadframe Structure for Reducing Mutual Inductance
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Solution Overview
Problem
Conventional leadframe type packages with multiple conductive wires experience increased mutual inductance due to limited distances between wires, limiting the reduction of total inductance and leading to power bounce and noise coupling.
Innovation Solution
The design includes a leadframe with a plurality of conductive wires connected to multiple power leads, increasing the distance between wires to reduce mutual inductance, and a specific arrangement of differential signal and power leads to optimize signal transmission modes, such as half-duplex and full-duplex, within a lead lane structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple conductive wires are connected to the same lead in parallel to reduce self inductance, then self inductance is reduced, but mutual inductance increases due to limited distances between wires
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of conductive wires to a three-dimensional立体 structure by introducing vertical stacking of lead lanes. Multiple lead lanes are arranged in different vertical layers, allowing conductive wires to be positioned at different heights (Z-axis) while maintaining horizontal separation. This dimensional change enables simultaneous reduction of both self inductance (through parallel connections) and mutual inductance (through increased spatial separation in 3D space).
Solution Approach 2:
The patent divides the single lead structure into multiple segmented lead lanes, where each lead lane contains separate conductive wires that can be independently positioned. This segmentation allows the conductive wires to be distributed across different spatial locations and vertical layers, reducing their mutual coupling while maintaining the parallel connection benefit for lowering self inductance.
2Area of stationary object
If differential signal leads are arranged in a compact lead lane structure to reduce package size, then area is reduced, but signal integrity deteriorates due to increased noise coupling
Solution Approach 1:
The patent arranges differential signal leads in compact lead lanes with precise spatial positioning, utilizing vertical stacking to separate signal pairs from noise sources. The differential pairs are positioned adjacent to each other for compactness, while power leads and ground leads are placed in different vertical layers to minimize noise coupling, achieving both small area and good signal integrity.
Solution Approach 2:
The patent applies different spatial arrangement strategies to different types of leads within the lead lane structure. Differential signal leads are positioned close together for noise immunity, while power leads are separated vertically from signal leads to reduce electromagnetic interference. This localized optimization of lead positioning minimizes noise coupling while maintaining compact overall dimensions.
Data Source
AI summary
A leadframe for a leadframe type package includes a chip base, and leads constituting lead lanes. One lead lane includes a pair of first differential signal leads, a pair of second differential signal leads, a pair of third differential signal leads between which and the pair of first differential signal leads is arranged the pair of second differential signal leads and a first power lead arranged between the pair of first and second differential signal leads. One of the pairs of differential signal leads has half-duplex transmission mode and two of the other pairs of differential signal leads have full-duplex transmission mode.