High-frequency module separate ground paths
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Solution Overview
Problem
High-frequency switch modules with a common ground electrode connection between ESD devices and switch ICs suffer from current surges that damage the switch IC and SAW filter elements due to shared ground paths, leading to malfunction and destruction.
Innovation Solution
A high-frequency switch module design with separate ground connection paths for the ESD device and switch IC, using a multilayer substrate with distinct plane electrode patterns and via holes to prevent direct current surge entry into the switch IC and SAW filter elements, and optionally incorporating a capacitor in series with the transmission line for enhanced surge tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common ground electrode is used to connect both the ESD device and switch IC to ground, then the grounding structure is simplified, but current surges from the ESD device enter the switch IC through the shared ground path, causing malfunction and damage
Solution Approach 1:
The common ground electrode is divided into separate ground electrodes: a first ground electrode connected to the ESD device and a second ground electrode connected to the switch IC. These separate ground electrodes are electrically isolated from each other, preventing current surges from the ESD device from entering the switch IC through the ground path.
2Reliability
If the ESD device is mounted on the multilayer substrate, then ESD protection is provided, but a ground connection line must be provided in the substrate, increasing substrate complexity and potential surge pathways
Solution Approach 1:
The ground connection structure is segmented into separate ground electrodes and isolated ground paths. The first ground electrode connects to the ESD device through dedicated via holes, while the second ground electrode connects to the switch IC through separate via holes, eliminating the need for a complex shared ground network in the substrate.
3Reliability
If separate ground connection paths are provided for the ESD device and switch IC, then current surges are prevented from entering the switch IC, but the grounding structure becomes more complex
Solution Approach 1:
The ground connection structure is segmented into spatially separated first and second ground electrodes with isolated connection paths. The first ground electrode serves the ESD device while the second ground electrode serves the switch IC, with no electrical connection between them in the substrate, simplifying the overall design while providing surge protection.
Data Source
AI summary
A high-frequency switch module includes an ESD device, a switch IC, and a SAW filter element that are mounted on the surface of a multilayer substrate. A ground-side land for the ESD device is connected to an external-connection ground electrode for the ESD device by via holes and plane electrode patterns. A ground connection land for the switch IC and a ground connection land for the SAW filter element are connected to a common inner ground electrode by via holes, and are connected to a common external-connection ground electrode by via holes and another common inner ground electrode.