Integrated Common Mode Filter and ESD Protection
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Solution Overview
Problem
In high-speed data transmission systems, existing configurations that use noise filters and ESD protection circuits on PCBs occupy large area, making them disadvantageous for mobile electronic devices and costly to implement.
Innovation Solution
A semiconductor component with a common mode filter monolithically integrated using thick polyimide layers, which reduces capacitance and eddy currents, and is combined with an ESD protection device to provide noise filtering and transient voltage protection in a compact, cost-effective manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noise filters and ESD protection circuits are mounted separately on PCB, then protection and filtering functions are provided, but large area is occupied on the PCB
Solution Approach 1:
The patent combines the common mode filter and ESD protection circuit into a single integrated semiconductor component. The filter includes coils formed on a substrate with ESD protection devices connected to the coils, merging two previously separate functions (noise filtering and transient protection) into one unified structure that occupies minimal PCB area while providing both protection and filtering functions simultaneously.
2Reliability
If multiple separate components are used for filtering and protection, then functional requirements are met, but implementation cost increases
Solution Approach 1:
The patent integrates multiple functional elements (coils, ESD protection devices, and interconnections) into a single semiconductor component that can be manufactured as one unit. This consolidation reduces the number of separate components needed, simplifies assembly processes, and lowers overall implementation cost while maintaining both noise filtering and transient protection capabilities.
3Reliability
If thick polyimide layers are used in filter construction, then capacitance and eddy currents are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent specifies using thick polyimide layers (with thickness greater than 3 micrometers) as the dielectric material between coils. This parameter change in layer thickness directly reduces parasitic capacitance and eddy currents, improving filter performance. The manufacturing complexity is managed by incorporating this thick layer into the standard semiconductor fabrication process flow.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides effective noise filtering and transient voltage protection in a small outline, low profile, single package, with a differential bandwidth up to at least 6 GHz and nominal common mode rejection, while being cost-efficient and reducing die area usage.
Implementation Method 1
A first thick polyimide layer, e.g., having a thickness greater than about 3 micrometers (μm), is formed over the semiconductor substrate
Implementation Method 2
A first thick polyimide layer, e.g., having a thickness greater than about 3 micrometers (μm), is formed over the semiconductor substrate
Data Source
AI summary
A common mode filter coupled to a protection device. In accordance with an embodiment, the common mode filter has first and second coils, each coil having a spiral shape, a central region, an exterior region, a first terminal, and a second terminal, wherein the first terminal of the first coil is formed in a first portion of the central region, the first terminal of the second coil is formed in a second portion of the central region, and wherein the central region is laterally bounded by the first and second coils and the exterior region is not surrounded by the first and second coils. The protection device has a first terminal coupled to the first terminal of the first coil and a second terminal coupled to the first terminal of the second coil.