Operational amplifiers (op amps) are key functional blocks that are used in a variety of analog subsystems such as switched-capacitor filters, analog-to-digital converters, digital-to-analog converters, voltage references and regulators, etc. There has been a growing interest in using such circuits for "extreme environment" electronics, in particular for electronics capable of operating down to deep-cryogenic temperatures for lunar and Martian surface explorations.
This thesis presents the design and analysis of a general purpose op amp suited for “extreme environment” applications, with a wide operating temperature range of 93 K to 398 K. The op amp has been implemented using a CMOS architecture to exploit the low temperature operational advantages offered by MOS devices, such as increase in carrier mobility, increased transconductance, and improved switching speeds. The op amp has a two-stage architecture to provide high gain and also incorporates common-mode feedback around the input stage. Tracking compensation has been implemented to provide stable frequency compensation over wide temperature. The op amp has been fabricated in a commercial 0.35-μm 3.3-V SiGe BiCMOS process. The op amp has been tested for the temperature range of 93 K to 398 K and is unity-gain stable and fully functional over this range.
This thesis begins with a study of the impact of temperature on MOS devices and operational amplifiers. Next, the design of the wide temperature general-purpose operational amplifier is presented along with an analysis of the common-mode feedback circuit. The op amp is then characterized using simulation results. Finally, the test setup is presented and the measurement results are compared with those from simulation.
| Identifer | oai:union.ndltd.org:UTENN/oai:trace.tennessee.edu:utk_gradthes-1360 |
| Date | 01 May 2007 |
| Creators | Ulaganathan, Chandradevi |
| Publisher | Trace: Tennessee Research and Creative Exchange |
| Source Sets | University of Tennessee Libraries |
| Detected Language | English |
| Type | text |
| Source | Masters Theses |
Page generated in 0.0054 seconds