RF Amplifier Circuit Video Bandwidth via Low Inductance Packaging
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Solution Overview
Problem
Conventional RF power amplifier circuits suffer from insufficient video bandwidth performance, signal distortion, and linearity degradation, failing to meet modern telecommunications standards, especially with the increasing wideband signal modulations in mobile communication applications.
Innovation Solution
Embedding a large value capacitance (in the μF or 10 μF range) close to the amplifying device in the RF amplifier circuit with a low inductive connection, utilizing the available space inside the packaging to reduce overall inductance and enhance video bandwidth performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional discrete RF amplifier circuits are used with standard packaging, then the device structure is simple and manufacturing is easy, but the video bandwidth performance is insufficient and signal distortion occurs
Solution Approach 1:
The patent merges the capacitor and inductor functions into a single integrated component structure within the package. The capacitor is formed using conductive layers on the package lid and substrate, while the inductor is created using bond wires connecting the capacitor to the transistor, combining multiple passive components into a unified arrangement that improves video bandwidth without proportionally increasing complexity
Solution Approach 2:
The patent utilizes the third dimension by forming the capacitor on the lid of the package rather than planar placement on the substrate. This vertical arrangement allows the capacitor to be positioned close to the transistor for low inductance connection while using the available package volume efficiently, thereby improving video bandwidth performance without increasing the package footprint
2Reliability
If bond wires are used to connect capacitors to the transistor, then the device is easy to manufacture, but the inductance is too high which limits video bandwidth
Solution Approach 1:
The patent changes the inductance parameter by optimizing the bond wire configuration and reducing the loop area formed by the connections. The capacitor is positioned and connected in a manner that minimizes the inductive path, and the package structure itself is designed to provide low-inductance pathways, thereby reducing overall inductance to extend video bandwidth
3Reliability
If internal package space is utilized to embed capacitance, then the video bandwidth increases significantly, but the package design becomes more complex
Solution Approach 1:
The package structure serves dual purposes: it provides mechanical protection for the transistor and simultaneously functions as part of the RF circuit by forming the capacitor and inductor elements. The lid and substrate are designed to create the capacitor structure, and the bond wires serve both as mechanical support and as the inductive element, allowing the package to contribute actively to the circuit performance while maintaining manufacturability
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 approach increases the video bandwidth by approximately 70%, meeting modern telecommunications standards and improving signal distortion and linearity, while being cost-effective and straightforward to implement.
Implementation Method 1
embedding a large value capacitance (in the μF or 10 μF range, for example) in a discrete (i.e. packaged) RF amplifier circuit so that is connected as close as practically possible to the amplifying device with a very low inductive connection
Implementation Method 2
The bond-wire connection between the gate-side capacitor 16g (Cpr) and the gate terminal G of the package has an inductance denoted Lg2, and the bond-wire connection between the gate-side capacitor 16 (Cpr) and the gate of the transistor on the die (DIE) has an inductance denoted Lg1
Data Source
AI summary
Radio Frequency (RF) amplifier circuits are disclosed which may exhibit improved video/instantaneous bandwidth performance compared to conventional circuits. For example, disclosed RF amplifier circuits employ various concepts for reducing an overall circuit inductance or enabling an increase in capacitance for a given circuit size.