Power Amplifier Module Ground Terminals for Short Return Paths
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Solution Overview
Problem
In power amplifier modules, providing an adequate ground reference for power transistor dies becomes challenging when the thermal path for heat dissipation extends away from the system PCB, affecting the efficiency and performance of the amplifier.
Innovation Solution
The power amplifier module is mounted in a 'flipped orientation' with the embedded heat dissipation structure facing away from the system substrate, and specialized ground terminals are positioned close to the power transistor dies to create a short, optimized ground return current path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thermal path for heat dissipation extends away from the system PCB, then heat removal capability is improved, but the ground reference quality deteriorates
Solution Approach 1:
The invention separates the thermal dissipation function from the ground reference function by using distinct structures: thermal vias with thermal conductive material for heat removal, and dedicated ground terminals with ground conductive material for ground reference. This segmentation allows each function to be optimized independently, resolving the contradiction between heat dissipation capability and ground reference quality.
Solution Approach 2:
The invention introduces an intermediary ground terminal structure that provides a direct ground reference path to the power transistor die without relying on the thermal path. The ground terminal includes ground conductive material that electrically connects to the ground layer and extends to contact the power transistor die, acting as a mediator between the ground layer and the die to ensure adequate ground reference even when thermal paths are optimized for heat removal.
2Ease of manufacture
If ground terminals are positioned away from power transistor dies, then manufacturing simplicity is improved, but return current path length increases
Solution Approach 1:
The invention applies local quality by positioning ground terminals with ground conductive material in close proximity to power transistor dies specifically where ground reference is needed, while other areas of the circuit board maintain standard manufacturing layouts. This localized approach to ground terminal placement minimizes return current path length for critical components without requiring complete redesign of the entire manufacturing process.
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 configuration ensures proper grounding and minimizes performance reductions, maintaining efficiency and gain by reducing the electrical length of the return current path, thereby enhancing the overall performance of the power amplifier module.
Implementation Method 1
heat generated by the power transistor die is dissipated through the ground/thermal dissipation structure(s)
Implementation Method 2
The first ground terminal is electrically coupled to the ground contact of the power transistor die
Data Source
AI summary
An amplifier module includes a module substrate with a mounting surface, a signal conducting layer, a ground layer, and a ground terminal pad at the mounting surface. A thermal dissipation structure extends through the module substrate. A ground contact of a power transistor die is coupled to a surface of the thermal dissipation structure. Encapsulant material covers the mounting surface of the module substrate and the power transistor die, and a surface of the encapsulant material defines a contact surface of the amplifier module. A ground terminal is embedded within the encapsulant material. The ground terminal has a proximal end coupled to the ground terminal pad, and a distal end exposed at the contact surface. The ground terminal is electrically coupled to the ground contact of the power transistor die through the ground terminal pad, the ground layer of the module substrate, and the thermal dissipation structure.