Capacitive Interfaces for Monolithic Integrated Sensors
Surface micromachining has become an established technology for inertial sensing. Compatibility with standard IC fabrication processes enables monolithic integration of the sensing element and interface electronics for reduced size and power dissipation, simplified packaging, and increased functionality. The need to resolve sub-Angstrom displacements poses a challenge on the interface. Capacitive pickups are attractive since they do not require special processing and because of their dual function as sensor and electrostatic actuator. The principles and practical considerations for capacitive sensor interfaces are discussed along with circuit examples including a precision sensor with a 3×10-12m/rt-Hz position measurement noise floor.
KeywordsResonant Frequency Flicker Noise Noise Floor Sense Capacitor Differential Pair
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