Oscillator Conductor Layer Placement for Phase Noise
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Solution Overview
Problem
Existing oscillators with inductors integrated inside the IC face deterioration in characteristics due to the magnetic field being blocked by the conductor layer at ground potential, affecting oscillation and phase noise characteristics.
Innovation Solution
The oscillator design includes a substrate with a conductor layer that overlaps the resonator interconnections but not the inductor, preventing magnetic field interference and stabilizing oscillation characteristics, while allowing for compact mounting of the IC with an integrated spiral inductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the conductor layer at ground potential overlaps the inductor to provide shielding and stabilize oscillation characteristics, then the oscillation stability is improved, but the magnetic field of the inductor is blocked and the inductor characteristics deteriorate
Solution Approach 1:
The substrate surface is divided into distinct regions: a first region for the resonator interconnection and a second region for the inductor. The conductor layer is selectively positioned only in the first region, creating spatial segmentation that allows the conductor layer to provide shielding for the resonator interconnection while avoiding the inductor region to prevent magnetic field blocking.
Solution Approach 2:
The conductor layer is applied locally only where needed for shielding purposes (overlapping the resonator interconnection) rather than uniformly across the entire substrate. This local quality approach ensures that the shielding benefit is provided precisely where electromagnetic interference needs to be reduced, while the inductor region maintains its magnetic field integrity.
2Volume of moving object
If the inductor is integrated inside the IC to reduce oscillator size, then the device size is reduced, but the magnetic field may be blocked by the conductor layer at ground potential
Solution Approach 1:
The substrate is segmented into a first region for resonator interconnection and a second region for the inductor. The conductor layer is selectively formed only in the first region, creating a spatial separation that allows compact integration of the inductor within the IC while preventing the conductor layer from blocking the inductor's magnetic field.
Solution Approach 2:
The substrate structure acts as an intermediary that mediates between the need for compact integration and magnetic field integrity. By designing the substrate with distinct regions and selective conductor layer placement, the substrate enables the inductor to be integrated inside the IC while simultaneously protecting it from magnetic field blocking by the conductor layer.
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 improves phase noise characteristics by up to 2 dBc/Hz and stabilizes oscillation characteristics, preventing magnetic field blockage and maintaining efficient frequency adjustment.
Implementation Method 1
the conductor layer at the ground potential overlaps the interconnections constituting an oscillation loop and the IC, and thus, stabilization of capacitances and oscillation characteristics is achieved
Data Source
AI summary
In the oscillator, a quartz crystal resonator and an oscillation circuit formed in an IC incorporating an inductor are electrically coupled to each other with a resonator interconnection disposed on a surface of a substrate to form an oscillation loop. A conductor layer disposed as an intermediate layer of the substrate is disposed so as to overlap the resonator interconnection and not to overlap the inductor incorporated in the IC in a plan view.