Two-Piece Shielded PCB Connector ESD Tolerance
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Solution Overview
Problem
Known shielded connectors for industrial Ethernet applications allow high-frequency electrical noise to couple with data signals due to electrostatic discharge, compromising system immunity and degrading communication speeds when traditional noise suppression methods are used.
Innovation Solution
A two-piece electrically isolated shield design for PCB-mounted connectors, where the first part is connected to earth or chassis ground and the second part shields the remaining areas from electromagnetic interference, creating an open space to prevent noise coupling and maintain high-speed communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a continuous shield is used to block electromagnetic interference, then EMI shielding effectiveness is improved, but noise coupling to data signals increases due to ESD pathways
Solution Approach 1:
The shield is divided into two separate parts: a first shield part and a second shield part, which are electrically isolated from each other. This segmentation breaks the continuous ESD pathway while maintaining EMI shielding effectiveness, as each part can be independently connected to ground without creating a noise coupling pathway to the data signals.
2Object-affected harmful factors
If noise suppression components (capacitors and diodes) are added to the signal path, then electrical noise is suppressed, but high-speed communication performance degrades
Solution Approach 1:
The noise suppression function is extracted from the signal path and implemented through the segmented shield structure itself. By providing separate ESD pathways through the first and second shield parts, the harmful noise is diverted away from the data signals without requiring capacitors or diodes in the signal path, thus maintaining high-speed communication performance.
3Reliability
If the shield is connected in a DC path to chassis ground, then ESD protection is improved, but ground currents through equipment increase
Solution Approach 1:
The shield connection to ground is segmented into separate pathways through the first and second shield parts. This allows ESD protection to be achieved by providing dedicated ESD discharge paths without creating a continuous DC ground path that would conduct ground currents through the equipment.
4Object-generated harmful factors
If the shield is intentionally disconnected from DC ground path, then ground currents are avoided, but noise coupling to communication signals increases due to parasitic inductance
Solution Approach 1:
The shield is segmented into two electrically isolated parts, each capable of being connected to ground independently. This segmentation allows the shield to avoid DC ground path currents while still providing effective noise suppression, as each segment can be optimally connected without creating parasitic inductance issues in a continuous path.
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
Effectively suppresses electromagnetic interference while maintaining high-speed data communication by physically and electrically disconnecting the shield parts, thereby reducing noise coupling and enhancing system immunity to electrical noise.
Implementation Method 1
an electrically conductive shield that covers part of the body and that includes: (i) a first shield part; and (ii) a second shield part that is physically disconnected from the first shield part and that is electrically isolated from the first shield part
Data Source
AI summary
A shielded connector includes a body with a socket adapted to receive a cable termination plug. Connector contacts in the socket mate with contacts of the cable plug. Connector pins project from the body and are operably coupled to the connector contacts in the socket. An electrically conductive shield covers part of the body and includes (i) a first shield part; and (ii) a second shield part physically disconnected from the first shield part and electrically isolated from the first shield part such that an open space separates the first shield part from the second shield part. The first shield part includes a cable shield contact located adjacent the socket that electrically mates with the EMI shield termination contact of the plug. The first and second shield parts further include respective first and second shield connector pins to physically and electrically connect the shield with an associated printed circuit board for dissipation of electrical charges from the first and second shield parts.