Jens Verbeeck

Conceptual design of a MGy tolerant integrated signal conditioning circuit in 130nm and 700nm CMOS

The conceptual design of a MGy tolerant configurable discrete time signal conditioning circuit in a 130nm and 700nm CMOS technology is presented, for use with resistive sensors like strain gauge pressure sensors. The design features a differential preamplifier using a Correlated Double Sampling (CDS) architecture at a sample rate of 20kHz. Furthermore, a high voltage buffer and level shifter is presented in the 0.7μm design. The gain is digitally controllable between 27 and 400. The nominal input referred noise voltage is only 8.6μV at room temperature. The circuits have a simulated radiation tolerance of more than 1MGy. Simulations of the radiation behaviour are based on results obtained from [1],[2].

Design and Assessment of a Robust Voltage Amplifier with 2.5 GHz GBW and >100 kGy Total Dose Tolerance

A differential voltage amplifier with a gain-bandwidth product of 2.5Ghz and using adaptive biasing has been designed in a standard CMOS technology and assessed under radiation and temperature variations. The principle used in this ASIC will be employed in the design of a Gbps TIA with improved tolerance for ?-irradiation and temperature for an optical instrumentation (LIDAR) receiver aiming at operation in harsh environments. The voltage amplifier was tested under gamma radiation and features a gain degradation of merely 4.5% up to a total dose of 100kGy. In order to verify the radiation effects on the IC, the threshold voltage shift of the separate transistors has been investigated. Temperature characterization has shown that the amplifier features a reduction of the voltage gain by only 5.6% for a temperature range of -40 till 130 ?C.

A MGy, Low-Offset Programmable Instrumentation Amplifier IC for Nuclear Applications

This paper shows a customized MGy radiation tolerant instrumentation amplifier. The 65 nm CMOS-based ASIC amplifier has an offset smaller than 1 μV and a noise level below 50 nV/√Hz from DC. It consumes less than 5 mW and has a common-mode-rejection-ratio larger the 100 dB. In addition, it allows a programmable gain setting from 8,16,32,64,128 to 256. The performance of this instrumentation amplifier was monitored during an on-line radiation experiment up to a total ionizing dose larger than 1 MGy, enabling the read-out of the most common nuclear temperature and position sensors.

Radiation effects upon the mismatch of identically laid out transistor pairs

This paper presents the DC behavior of transistors with finger layout and with gate enclosed layout in a 0.18μm CMOS technology under the influence of gamma-radiation. The threshold voltage shift and the drain current mismatch before and after irradiation has been investigated up to a total ionizing dose of 100kGy.

Design of a MGy tolerant instrumentation amplifier using a correlated double sampling technique in 130 nm CMOS

In this paper a radiation tolerant configurable instrumentation amplifier for use with resistive sensors, like strain gauge pressure sensors, is presented. The design features a 1.5 V differential amplifier, consuming 1.5 mW and utilizing a correlated double sampling technique (CDS) with a sample frequency of 20 kHz. The gain of the amplifier is digitally configurable between 27 and 400 and the input referred noise density equals 8.6 µV at room temperature. The circuit has a simulated radiation tolerance exceeding 1 MGy.

Electronic Components Exposed To Nuclear Radiations In Iter Diagnostic Systems: Current Investigations And Perspectives

The ITER diagnostics systems will have sensors (e.g. cameras, detectors) and signal conditioning electronic components (e.g. preamplifiers) located in the Tokamak building and in particular in the port-cell area. These components will be exposed to gamma and neutron fluxes from the plasma, from the activated water circulating in the pipes of the water cooling system and from the cask transporting activated components during maintenance operation. Potential damage caused by the nuclear radiation range from function degradation (e.g. signal corruption) to component destruction. Neutronic calculations show that the total ionizing dose and neutron fluence are higher than what commercial components can withstand. In this context, an expert study for the selection of tolerant electronic components for the ITER diagnostic systems has been recently carried out. This paper is based on the outcome of this report. First the different options to mitigate radiation effects are reviewed and assessed according to the draft ITER policy presently under discussion on electronic exposed to nuclear radiation. Next, several options are elaborated based on the requirements for individual diagnostic systems (e.g. magnetics, neutronics, bolometers) with main focus on preamplifiers, ADCs and optical converters. The options include proposal of available commercial off-the-shelf components with shielding, or components already qualified for radiation hard environment (e.g. for space applications), or development of custom components. Evaluation criteria include availability, integration issues, cost, as well as development effort in case of a special development option is taken.

MGy Radiation Assessment of a Space-Graded Amplifier and ADC

This paper shows a high total dose radiation assessment on a set of space qualified components. Two space graded COTS (Commercial off-the-shelf) components were selected and monitored under 60Co gamma radiation, namely an instrumentation amplifier and a 14 bit analogue-to-digital-converter (ADC). The specifications of these COTS components were monitored on-line with a customized test bed, up-to a total ionizing dose larger than 1 MGy and are presented in this paper.

A 1 MGy TID Radiation-Tolerant 56 µW CMOS Temperature Sensor with ±1.7°C Accuracy

The total-ionizing-dose (TID) radiation tolerance of CMOS temperature sensors is generally limited by the radiation-introduced leakage current in diodes. A dynamic base leakage compensation technique is employed to improve the radiation hardness of the CMOS temperature sensor. The fabricated temperature sensor achieves an accuracy of ±1.7°C from -40°C to 125°C, while the power and area consumption are only 56 μW and 0.07 mm2, respectively. The temperature sensor is assessed with a gamma irradiation experiment with a dose rate of 1 kGy/h, and radiation induced temperature readout drifts are smaller than 0.2% after 1 MGy.

A > 4 MGy radiation tolerant 8 THzOhm transimpedance amplifier with 50 dB dynamic range

A 130 nm Transimpedance Amplifier has been developed with a 255 MHz bandwidth, 90 dBΩ transimpedance gain and a dynamic input range of 1:325 or 50 dB for a photo-diode capacitance of 0.75 pF. The equivalent integrated input noise is 160 nA @ 25°C. The gain of the voltage amplifier, used in the transimpedance amplifier (TIA), degrades less than 3% over a temperature range from -40 °C up to 125 °C. The TIA and attenuator exhibit a radiation tolerance larger than 4 MGy, as evidenced by radiation assessment.