Monolithic Resistor Voltage Stability via Stacked Metal Wires
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Solution Overview
Problem
Monolithic resistors in audio applications exhibit significant voltage-induced resistance variations, leading to distortion in Hi-Fi sound production, as they are sensitive to terminal voltages, which existing poly-type and diffusion-type resistors fail to mitigate effectively.
Innovation Solution
The development of monolithic resistors formed by series or parallel connections of stacked metal wires, which are less sensitive to terminal voltages, utilizing configurations such as inverting and current-mode amplifiers, and combinations with poly or diffusion materials to minimize resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If poly-type or diffusion-type resistors are used in monolithic implementation, then the resistor can be fabricated using standard CMOS or bipolar technology, but the resistance varies significantly with applied terminal voltage causing distortion
Solution Approach 1:
The patent combines metal wires (with low voltage coefficient) with poly or diffusion resistors (with high voltage coefficient) in a parallel configuration. The metal component provides voltage-insensitive resistance while the poly/diffusion component is designed to have matching terminal voltages to the metal, thereby canceling out voltage-induced resistance variations and achieving high reliability without sacrificing manufacturability
Solution Approach 2:
The patent changes the voltage coefficient parameter by introducing metal wires with inherently lower voltage coefficients into the resistor structure. By adjusting the proportion and configuration of metal versus poly/diffusion materials, the overall voltage coefficient of the composite resistor is optimized to minimize resistance variation with applied voltage
2Reliability
If metal wires are used to reduce voltage-induced resistance variations, then resistance stability improves, but the device complexity increases due to stacked wire configurations
Solution Approach 1:
The patent divides the resistor into multiple stacked metal wire segments connected in parallel, where each segment contributes to the overall resistance while providing voltage insensitivity. This segmentation allows the complex function of voltage-stable resistance to be achieved through simpler individual metal wire elements, making the overall design more manageable despite the multi-component structure
Data Source
AI summary
In one embodiment, an apparatus comprising a first resistor, the first resistor comprising a first type of resistor having a plurality of metal wires in respective layers, the plurality of metal wires arranged in series via a plurality of vias.