Multistage Amplifier Ground Plane Segmentation for Oscillation Control
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Solution Overview
Problem
Multistage amplifiers in high-frequency bands face instability due to feedback through a common ground plane, leading to oscillation and poor performance, as existing methods like separating chip mounting patterns are difficult to stabilize and influence by wire inductances.
Innovation Solution
An integrated circuit design with separate ground planes for each amplifier stage connected by ground lines with specific length and width ratios, where the center line length is between 10 μm to 1 mm and the width is ⅓ or less of the plane width, to control impedance and suppress feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common ground plane is used for multiple amplifier stages, then the circuit layout is simplified and manufacturing is easier, but feedback through the ground plane causes oscillation and instability
Solution Approach 1:
The ground plane is segmented into multiple separate ground regions, each dedicated to a specific amplifier stage. These segmented ground regions are connected through high-impedance transmission lines rather than a continuous ground plane, preventing feedback while maintaining manufacturing feasibility.
2Reliability
If chip mounting patterns are separated in units of amplifying devices to suppress oscillation, then circuit stability improves, but wire inductances influence characteristics and stabilization becomes difficult
Solution Approach 1:
Each amplifier stage is provided with its own dedicated ground region with specific impedance characteristics optimized for that stage. The ground connection lines are designed with controlled impedance and specific length/width ratios to provide appropriate isolation while maintaining signal integrity.
3Reliability
If ground lines with specific dimensions are used to connect separate ground planes, then feedback is suppressed and stability improves, but manufacturing precision requirements increase
Solution Approach 1:
The ground lines are designed with specific length and width parameters that create high impedance at operating frequencies, suppressing feedback. The length is set to 10μm to 1mm and width to 1/3 or less of the ground plane width, creating resonant conditions that block feedback paths while remaining manufacturable.
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 stabilizes the multistage amplifier operation by reducing reflection coefficients and maintaining high gain, while avoiding the need for separated chip mounting patterns, thus enhancing performance and miniaturization potential.
Implementation Method 1
at least one line for ground connecting the first plane and the second plane to each other, wherein the at least one line has a center line having a length of 10 μm to 1 mm, a width of the at least one line is 1⁄3 or less of a width of the first plane, and a pattern ratio which is a value obtained by dividing the length of the center line by the width of the at least one line is 1 or more
Data Source
AI summary
According to the present invention, an integrated circuit includes a first amplifier stage, a second amplifier stage, a first signal line connecting an output of the first amplifier stage and an input of the second amplifier stage to each other, a first plane for ground connected to the first amplifier stage, a second plane for ground connected to the second amplifier stage and at least one at least one line for ground connecting the first plane and the second plane to each other, wherein the at least one line has a center line having a length of 10 μm to 1 mm, a width of the at least one line is ⅓ or less of a width of the first plane, and a pattern ratio is 1 or more.