| Delta-Sigma A/D converters (ADC) can achieve high resolutions with relatively simple circuit complexity and by using low precision analog components, being nowadays the preferred approach for low and medium frequency applications. Delta-Sigma modulator (the core of the Delta-Sigma ADC) can be implemented either by using discrete-time circuitry or by using continuous-time one. Compared to discrete-time ones, continuous-time Delta-Sigma modulators can operate at higher sampling frequencies, consume less power, and provide implicit anti-alias filtering.; In space applications, an ADC must satisfy, besides the requirements of wide bandwidth and high resolution, additional ones concerning radiation hardness. Among all radiation effects in electronic circuits, probably the most difficult to characterize are single event effects (SEEs). Depending on the type of the circuit hit (digital or analog) and on the energy of the striking particle, one can have different effects induced by SEEs.; Silicon on insulator (SOI) CMOS technology can achieve higher operation speed and lower power dissipation than traditional bulk CMOS processes with its special structure and technical advantages. One distinct advantage of SOI CMOS is its radiation hardness compared to bulk CMOS, which makes it desirable in space and military applications.; The research effort within this thesis is focused on developing a class of SOI CMOS mixed-signal systems, specifically Delta-Sigma A/D converters, to be used in radio receivers for space communications. Besides trying to meet the technical specifications required by space communication systems (resolution, bandwidth, operating temperature range), our efforts are directed towards implementing the circuits for low-power and radiation hardness (with a special emphasis on characterizing and reducing the SEEs). A prototype fourth-order single-bit continuous-time Delta-Sigma modulator is designed and implemented in a 0.35mu m SOI CMOS process from Honeywell. Both specification and radiation experimental results are presented. To achieve higher resolution and wider bandwidth, a fifth-order 5-bit continuous-time Delta-Sigma modulator is designed in Honeywell's 0.35mu m SOI CMOS process. Its circuit-level simulation results are presented. Finally SEEs in the continuous-time Delta-Sigma modulator are analyzed based on a novel SEEs model. |
