High performance CMOS capacitive interface circuits for MEMS gyroscopes

Download

index.pdf

Date

2006

Author

Silay, Kanber Mithat

Metadata

Show full item record

Item Usage Stats

352
views

277
downloads

This thesis reports the development and analysis of high performance CMOS readout electronics for increasing the performance of MEMS gyroscopes developed at Middle East Technical University (METU). These readout electronics are based on unity gain buffers implemented with source followers. High impedance node biasing problem present in capacitive interfaces is solved with the implementation of a transistor operating in the subthreshold region. A generalized fully differential gyroscope model with force feedback electrodes has been developed in order to simulate the capacitive interfaces with the model of the gyroscope. This model is simplified for the single ended gyroscopes fabricated at METU, and simulations of resonance characteristics are done. Three gyroscope interfaces are designed by considering the problems faced in previous interface architectures. The first design is implemented using a single ended source follower biased with a subthreshold transistor. From the simulations, it is observed that biasing impedances up to several gigaohms can be achieved. The second design is the fully differential version of the first design with the addition of a self biasing scheme. In another interface, the second design is modified with an instrumentation amplifier which is used for fully differential to single ended conversion. All of these interfaces are fabricated in a standard 0.6 m CMOS process. Fabricated interfaces are characterized by measuring their ac responses, noise response and transient characteristics for a sinusoidal input. It is observed that, biasing impedances up to 60 gigaohms can be obtained with subthreshold transistors. Self biasing architecture eliminates the need for biasing the source of the subthreshold transistor to set the output dc point to 0 V. Single ended SOG gyroscopes are characterized with the single ended capacitive interfaces, and a 45 dB gain improvement is observed with the addition of capacitive interface to the drive mode. Minimum resolvable capacitance change and displacement that can be measured are found to be 58.31 zF and 38.87 Fermi, respectively. The scale factor of the gyroscope is found to be 1.97 mV/(°/sec) with a nonlinearity of only 0.001% in ±100 °/sec measurement range. The bias instability and angle random walk of the gyroscope are determined using Allan variance method as 2.158 °/√hr and 124.7 °/hr, respectively.

Subject Keywords

Electronics.

URI

http://etd.lib.metu.edu.tr/upload/2/12607518/index.pdf
https://hdl.handle.net/11511/16288

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

High performance readout electronics for uncooled infrared detector arrays Yıldırım, Ömer Özgür; Akın, Tayfun; Department of Electrical and Electronics Engineering (2006) This thesis reports the development of high performance readout electronics for resistive microbolometer detector arrays that are used for uncooled infrared imaging. Three different readout chips are designed and fabricated by using a standard 0.6 m CMOS process. Fabricated chips include a conventional capacitive transimpedance amplifier (CTIA) type readout circuit, a novel readout circuit with dynamic resistance nonuniformity compensation capability, and a new improved version of the CTIA circuit. The fabr...
Reliability improvement of RF MEMS devices based on lifetime measurements Gürbüz, Ozan Doğan; Demir, Şimşek; Akın, Tayfun; Department of Electrical and Electronics Engineering (2010) This thesis presents fabrication of shunt, capacitive contact type RF MEMS switches which are designed according to given mm-wave performance specifications. The designed switches are modified for investigation in terms of reliability and lifetime. To observe the real-time performance of switches a time domain measurement setup is established and a CV (capacitance vs. voltage) curve measurement system is also included to measure CV curves, pull-in and hold-down voltages and the shifts of these due to actuat...
Development of electrochemical etch-stop techniques for integrated MEMS sensors Yaşınok, Gözde Ceren; Akın, Tayfun; Department of Electrical and Electronics Engineering (2006) This thesis presents the development of electrochemical etch-stop techniques (ECES) to achieve high precision 3-dimensional integrated MEMS sensors with wet anisotropic etching by applying proper voltages to various regions in silicon. The anisotropic etchant is selected as tetra methyl ammonium hydroxide, TMAH, considering its high silicon etch rate, selectivity towards SiO2, and CMOS compatibility, especially during front-side etching of the chip/wafer. A number of parameters affecting the etching are inv...
Implementation of a risc microcontroller using fpga Gümüş, Raşit; Güran, Hasan; Department of Electrical and Electronics Engineering (2005) In this thesis a microcontroller core is developed in an FPGA. Its instruction set is compatible with the microcontroller PIC16XX series by Microchip Technology. The microcontroller employs a RISC architecture with separate busses for instructions and data. Our goal in this research is to implement and evaluate the design in the FPGA. Increasing performance and gate capacity of recent FPGA devices permits complex logic systems to be implemented on a single programmable device. Such a growing complexity dema...
Millimeter wave gunn diode oscillators Lüy, Ülkü; Toker, Canan; Department of Electrical and Electronics Engineering (2007) This thesis presents the design and implementation of a millimeter-wave Gunn diode oscillator operating at 35 GHz (Ka (R) 26.5-40 GHz Band). The aim of the study is to produce a high frequency, high power signal from a negative resistance device situated in a waveguide cavity by applying a direct current bias. First the physics of Gunn diodes is studied and the requirements that Gunn diode operates within the negative differential resistance region is obtained. Then the best design configuration is selected...

Citation Formats

K. M. Silay, “High performance CMOS capacitive interface circuits for MEMS gyroscopes,” M.S. - Master of Science, Middle East Technical University, 2006.