RF Transistor Amplifier Package Layout for Lead Isolation
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Solution Overview
Problem
High power, high frequency RF transistor amplifiers face challenges in heat management and electromagnetic coupling, leading to performance deterioration and increased packaging costs due to rivet usage in molded plastic designs, which occupy space and limit design flexibility.
Innovation Solution
The RF transistor amplifier package incorporates a submount with strategically positioned rivets and isolation structures to reduce electromagnetic coupling between leads, optimizing lead configurations and eliminating rivets from corners to enhance space efficiency and electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rivets are used in molded plastic package designs to secure leads, then mechanical strength and lead fixation are improved, but electromagnetic coupling between leads increases and space efficiency decreases
Solution Approach 1:
The patent introduces an isolation structure as an intermediary element positioned between adjacent leads. This isolation structure acts as a mediator that blocks electromagnetic field coupling between leads while allowing the rivet to secure the lead assembly. The isolation structure is electrically connected to the rivet, creating a shielded environment that reduces mutual coupling without compromising the mechanical fixation function.
Solution Approach 2:
The patent extracts the electromagnetic shielding function from the rivet itself and separates it into a dedicated isolation structure. By taking out the shielding function, the design allows the rivet to focus on mechanical fixation while the isolation structure handles electromagnetic isolation, thereby reducing the harmful electromagnetic coupling effect without sacrificing lead fixation strength.
2Strength
If rivets are used in molded plastic package designs to secure leads, then mechanical strength and lead fixation are improved, but the internal area and design flexibility of the package are reduced
Solution Approach 1:
The patent moves the isolation structure into the vertical dimension by extending it upward from the rivet head. This dimensional transition allows the isolation structure to provide electromagnetic shielding without occupying additional lateral space on the package surface. The isolation structure rises in the Z-direction, effectively using the vertical dimension to resolve the space conflict.
Solution Approach 2:
The isolation structure is nested within the space already occupied by the rivet assembly. The isolation structure extends upward from the rivet head, utilizing the vertical space above the rivet rather than requiring additional lateral space. This nesting approach allows the isolation function to be integrated into the existing rivet footprint.
3Area of stationary object
If multiple leads are closely spaced to increase space efficiency, then area utilization is improved, but electromagnetic coupling between leads increases
Solution Approach 1:
The isolation structure serves as a mediator inserted between closely spaced leads. Even when leads are positioned close together to maximize space utilization, the isolation structure extends upward from the rivet to create an electromagnetic barrier. This mediator allows close lead spacing while preventing harmful mutual coupling through its shielding effect.
Solution Approach 2:
The isolation structure provides localized electromagnetic shielding precisely where needed - between adjacent leads. The shielding effect is concentrated in the regions between leads rather than requiring uniform spacing throughout the package. This local quality approach allows close spacing in non-critical areas while maintaining isolation where electromagnetic coupling would be harmful.
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
This design improves electrical isolation, reduces mutual coupling, and increases space efficiency within the package, leading to enhanced performance and cost-effectiveness by minimizing the impact of rivets on the package's internal area and electrical characteristics.
Implementation Method 1
an isolation structure that reduces mutual coupling between the first and second leads
Data Source
AI summary
A radio frequency (RF) transistor amplifier package includes a submount, and first and second leads extending from a first side of the submount. The first and second leads are configured to provide RF signal connections to one or more transistor dies on a surface of the submount. At least one rivet is attached to the surface of the submount between the first and second leads on the first side. One or more corners of the first side of the submount may be free of rivets. Related devices and associated RF leads and non-RF leads are also discussed.