Back-Gate Differential Power Amplifier for Parasitic Neutralization
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Solution Overview
Problem
Existing RF/mmWave differential power amplifier designs face issues with low gain, poor linearity, complex circuit layout, and high parasitic charges due to cross-over routings, which degrade performance and increase complexity.
Innovation Solution
A back-gate controlled differential RF/mmWave power amplifier with automatic parasitic neutralization and gain boost, utilizing a current division with back-gate control and a compact triple-well neighboring n-well layout on a fully depleted semiconductor-on-insulator (FDSOI) substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If two-cross capacitors are used with floating source circuit to cancel phase delay, then gain is high, but capacitance varies with signal swing level which compromises linearity
Solution Approach 1:
The patent changes the operating parameters by using back-gate voltage to control the auxiliary circuit devices, maintaining stable capacitance values that do not vary with signal swing level, thus preserving linearity while achieving high gain through the auxiliary devices
2Power
If reference source with two-cross capacitors is used to cancel phase delay, then gain may be improved, but cross-over routings increase parasitic charges and circuit complexity
Solution Approach 1:
The patent merges the auxiliary circuit devices with the main transistors by forming them in the same continuous active region, eliminating the need for separate reference source circuits and cross-over routings, thereby reducing parasitic charges and simplifying the overall circuit layout
3Power
If reference source with two-cross capacitors is used, then gain control is achieved, but layout becomes difficult without high gain degradation in RF/mmWave region
Solution Approach 1:
The auxiliary circuit devices are merged into the same continuous active region as the main transistors, enabling a compact layout that is easy to manufacture while maintaining effective gain control through back-gate voltage application in the RF/mmWave frequency range
4Power
If high swing level is achieved at a node, then signal amplitude is improved, but circuit oscillations increase
Solution Approach 1:
The auxiliary circuit devices act as intermediaries that provide controlled gain enhancement through back-gate voltage, allowing high signal amplitude at the output while maintaining circuit stability by preventing oscillations through proper biasing and feedback mechanisms
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to a differential circuit with automatic parasitic neutralization and gain boost and methods of manufacture. The structure includes a plurality of auxiliary circuit devices with back-gate controls to perform a boost gain, and a differential pair of circuit devices which are connected to the auxiliary circuit devices.