A 10-Bit,Low Power,Successive Approximation,Digitally Auto-Zeroed CMOS ADC Core for the NASA TRIO Smart Sensor System on a Chip

In spacecraft applications there is a great need for robust analogue to digital converters (ADC) that can withstand the harsh space environment. Commercially available ADCs cannot operate in the space environment due to radiation effects. In this paper we present an ADC that has been developed for the NASA TRIO smart sensor system on a chip (SoC), a versatile low power device specifically designed for spacecraft data acquisition and telemetry of several types of sensors such as temperature, voltage/current transducers, radFETs, etc. It is required for the ADC to operate in excess of 300 Krad total ionizing dose and to be robust to single event upsets. The successive approximation topology was chosen and it was enhanced with a special auto-zeroing technique to compensate for possible lifetime offset errors. Due to the comparator design, a rail-to-rail input capability is achieved, a feature very useful in some type of Vdd ratio metric sensors. It has 10-bit resolution for a reference in the range 0.1 to Vdd + 1 V, and for power supply in the range 2.5 to 5.5 V; the positive reference terminal V_ref+ is settable up to Vdd + 0.5 V and the negative voltage terminal is settable down to GND-0.5 V. The power dissipation is less than 2 mW at 50 Ksamlles/sec. The TRIO chip is used in several NASA spacecraft including CONTOUR, STEREO, MESSENGER, EUROPA, PLUTO, etc.George Kottaras was born in Athens, Greece in 1974. He received the Diploma degree (five years with thesis) in Electrical Engineering from Democritos University of Thrace, Greece in 1996. He is currently pursuing the Ph.D. degree on Scientific Space Instruments and spacecraft avionics at Space Research Laboratory, DUTh. He has specialized in VLSI technologies at JHU/APL for about five years.His research interests include mixed signal analog/digital design, ADCs, design for testability, testing, smart sensors and data acquisition.Nikolaos P. Paschalidis was born is Serres, Greece in 1963. He received the Diploma and Ph.D. degrees in Electrical Engineering from the Democritus University of Thrace (DUTh), Greece, in 1985 and 1992 respectively. He has been in appointment with the Johns Hopkins University, since 1989, where his research specialized in advanced microelectronics, space instrumentation, and space physics.He later joined the Space Department of JHU Applied Physics Laboratory (JHU/APL) Laurel, MD, as a postdoctoral fellow and presently he is Principal Staff. His research interests are in analog and mixed signal microelectronics, microsensors, microsystems and their applications in in-situ and remote sensing spacecraft instruments and avionics. He pioneered in the Advanced Technology Development program of NASA for smaller better faster missions by leading efforts in the circuit level of: amplifiers, comparators, voltage references, ADC and DAC, PLLs, TDCs, SEU and radiation tolerant design, physical design, design for testability, testing and space qualification; in the system on a chip level flight ready chips including: the Time of Flight chip for precise time pickoff and time digitization, Energy chip for radiation energy measurement, the TRIO smart sensor chip for spacecraft data acquisition and control etc; in the instrument and spacecraft level: application of these technologies in particle and plasma spectrometers, laser altimeters, photon/particle imagers, TOF mass spectrometers, X-ray and gamma-ray instruments, spacecraft avionics. Space missions using these technologies include: Cassini, Image, Contour, Messenger, Pluto, Mars missions, etc. Dr. Paschalidis published extensively in microelectronics, space instrumentation, and space physics. He supervises research of graduate students in ECE and Applied Physics. He supervised DUTh graduate students at JHU/APL for many years. He participates as principal investigator and co-investigator in several space programs; he participates in communities with space related activities including: the IEEE Aerospace, Nuclear Sciences, NASA VLSI, IAA, and American Geophysical Union.Emmanuel T. Sarris was bom in Athens, Greece, in 1945. He received the physics degree from the University of Athens in 1967 and the Ph.D. degree in space physics from the University of Iowa, Iowa City, in 1973.He was a Postdoctoral Fellow in the Applied Physics Laboratory, The Johns Hopkins University, Baltimore, MD, from 1974 to 1976. From 1976 to 1977, he was a Research Scientist at the Max-Planck-Institut. He has been a Professor of Electrodynamics, Department of Electrical Engineering, University of Thrace, Greece, and Director of the Laboratory of Electrodynamics and Space Research since 1977. He was the Director of the Institute of Ionospheric and Space Physics, National Observatory of Athens from 1990 to 1996. His research interests include space plasma electrodynamics, design, construction, and testing of space instrumentation, satellite communications, satellite remote sensing. He is coinvestigator in the international space missions: Ulysses, Geotail, Interball, Cluster. He is the author of 270 refereed publications and 300 presentations at international meetings. Dr. Sarris is a member of the COSPAR Council. He was elected Johns Hopkins Scholar Award in 1992 and received the Award for Academic Excellence in 1994.Nikos Stamatopoulos was born in Peloponnisos, Greece in 1969. He received the diploma degree (five years with thesis) of Electrical Engineering from Democritos University of Thrace, Greece in 1994. He is currently pursuing the Ph.D. degree on Scientific Space Instruments at Space Research Laboratory, DUTh. He has specialized in VLSI technologies with emphasis in low noise analog design at JHU/APL for about five years.His main research interests are on Analogue CMOS VLSI design for fast time acquisition.Kostas Karadamoglou was born in Macedonia, Greece, in 1970. He received the diploma degree (five years with thesis) of Electrical Engineering from Democritos University of Thrace, Greece in 1994. He is currently pursuing the Ph.D. degree on Scientific Space Instruments at Space Research Laboratory, DUTh. He has specialized in VLSI technologies with emphasis in high-speed digital design at JHU/APL for about five years.His main research interests are on the design of application specific Time to Digital Converters.Vassilis Paschalidis was born in Serres, Greece in 1964. He received the B.S. degree in Electrical Engineering from the Technological Institute of Kabala, Greece in 1988. He worked n the industry for electronic automation. He has specialized in VLSI technologies at JHU/APL for about five years with emphasis in physical design. His research interests include mixed signal analog/digital VLSI design.