Stacked Memory Module Mirror Image PCB Arrangement
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Solution Overview
Problem
Conventional stacked memory modules face issues with non-uniform signal lines, increased load impedance, and stability problems, which affect signal integrity and increase costs due to complex circuit designs and packaging requirements, especially in mirror symmetry applications like DIMM memory.
Innovation Solution
A stacked memory module with a mirror image arrangement where pins of one memory unit are connected to the upper face of a rigid PCB, and the pins of another memory unit are connected in a mirror image manner to the lower face, with two flexible PCBs on both sides providing uniform signal lines and conductive contacts for enhanced connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional stacked memory modules are used with pins connected in the same direction, then the structure is simple to implement, but the signal lines become non-uniform and load impedance increases, affecting signal integrity
Solution Approach 1:
The patent applies mirror image arrangement where the second memory unit's pins are arranged symmetrically opposite to the first memory unit's pins. This creates uniform signal path lengths from both memory units to the PCB, resolving the non-uniform signal line issue while maintaining the stacked structure's manufacturing simplicity
2Reliability
If mirror symmetry arrangement is applied to stacked memory units, then signal line uniformity is improved, but the cost increases due to complex circuit design and package requirements
Solution Approach 1:
The patent uses a single rigid PCB to serve multiple functions: it provides mechanical support for both memory units, establishes electrical connections for both units through its conductive patterns, and enables the mirror image arrangement. This multi-functional approach reduces the need for additional components and complex packaging structures
3Reliability
If multiple PCBs are stacked to connect memory units, then connectivity and signal uniformity are enhanced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines the functions of multiple PCBs into a single rigid PCB structure. The PCB integrates both connection points for the first and second memory units with their pins respectively, eliminating the need for separate PCB assemblies while maintaining uniform signal paths through careful circuit trace design
Data Source
AI summary
A stacked memory module is manufactured in mirror image arrangement and a method for the same. The pins of a first memory unit and pins of a second memory unit are electrically connected to an upper face and a lower face of a first printed circuit board made of rigid material. The pins of the second memory unit are in mirror image arrangement with respect to the pins of the first memory unit. Two second PCBs are made of flexible material and electrically connected to both sides of the first PCB. Conductive contacts such as gold fingers are electrically connected to circuit on the second PCB. The manufacture cost is reduced and manufacture process is simplified. The signal quality is enhanced because the signal paths are uniform and the load impedance is reduced.