Crystal Oscillator Output Electrode Layout for Parasitic Capacitance Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In crystal oscillators, the increased size of mounting electrodes to improve contact properties leads to a larger parasitic capacitance difference between adjacent electrodes, which deteriorates the frequency accuracy of the oscillation output signal.
Innovation Solution
The oscillator design includes a substrate with electrodes disposed in specific configurations to reduce the interval between output and second electrodes, increasing parasitic capacitance and minimizing the difference between parasitic capacitances between electrodes, thereby enhancing frequency accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mounting electrodes corresponding to the crystal terminals are increased in size to improve contact properties, then the contact property is improved, but the difference between parasitic capacitances increases and frequency accuracy deteriorates
Solution Approach 1:
The patent applies local quality by making the output electrode have a different shape (extending in the first direction beyond the end portion of the first crystal electrode) compared to conventional uniform electrodes. This local modification changes the parasitic capacitance distribution specifically in the region where the output electrode interacts with crystal electrodes, thereby balancing the parasitic capacitances without affecting the overall contact area of all electrodes
Solution Approach 2:
The patent changes the geometric parameters of the output electrode by extending it in the first direction beyond the end portion of the first crystal electrode. This parameter change (extending the electrode length in a specific direction) directly modifies the parasitic capacitance values, balancing the difference between C1 and C2 while maintaining adequate contact properties
2Reliability
If mounting electrodes are enlarged to ensure good electrical contact, then contact reliability improves, but parasitic capacitance imbalance increases causing frequency error
Solution Approach 1:
The output electrode is given a special local shape that extends in the first direction beyond the end portion of the first crystal electrode. This local structural differentiation allows the output electrode to have different parasitic capacitance characteristics compared to other mounting electrodes, specifically balancing the parasitic capacitance difference between the two crystal electrodes
Solution Approach 2:
The patent introduces asymmetry in the electrode configuration by making the output electrode extend asymmetrically in the first direction. This asymmetric design is intentional and specifically targets the balancing of parasitic capacitances, creating a non-uniform electrode layout that achieves frequency precision improvement
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 results in a highly accurate oscillation output signal by reducing parasitic capacitance differences and improving the frequency stability of the oscillator.
Implementation Method 1
a resonator element; a circuit element electrically coupled to the resonator element and configured to output a clock signal
Data Source
AI summary
An oscillator includes: a resonator element; a circuit element configured to output a clock signal; and a container accommodating the resonator element and the circuit element and including a substrate having a first surface. The substrate includes a first electrode provided on the first surface and electrically coupled to the resonator element, a second electrode electrically coupled to the resonator element, and an output electrode configured to output the clock signal. The first electrode and the second electrode are disposed side by side in a first direction. The output electrode is disposed adjacent to the first electrode in a second direction orthogonal to the first direction. When an end portion of the first electrode on a side close to the second electrode is defined as a first end portion, the output electrode includes a first region disposed closer to the second electrode side than the first end portion in the first direction.