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A hierarchical method for total dose effects simulation of large mixed signal circuits using VHDL-AMS is described. Simplified behavioral models (or macro-models) of small sub-circuits replace SPICE-level circuits. The behavioral models describe the electrical circuit behavior and its dependence on the radiation dose. The behavioral models of sub-circuits can be assembled into complex mixed signal circuits. As a result, the computational cost is reduced significantly compared to conventional SPICE-based methods. The VHDL-AMS method also allows bias-dependent total dose degradation to be coupled to the circuit and operational conditions. Simulation accuracy remains sufficient to determine critical performance metrics of the circuit as the circuit performance degrades with dose. Index Terms--Behavioral modeling, CMOS, mixed signal circuits, radiation effects, total ionizing dose (TID), VHDL-AMS.

A novel way to mitigate single event transients (SETs) in a comparator by using auto-zeroing techniques is presented. Two comparators, a folded cascode comparator and a novel auto-zeroed comparator, are simulated using a current pulse model for a single event strike. These simulations show that the novel auto-zeroed comparator transients are never longer in duration than a single auto-zero clock period. This compares favorably to a folded cascode comparator sample circuit, whose maximum transient duration is strongly dependent on the differential input voltage and can be four times as long. The use of the presented auto zero comparator can practically eliminate the comparator contribution to single event errors in many mixed signal circuits, such as analog-to-digital converters (ADCs). Index Terms--Analog-to-digital converters (ADCs), auto-zeroing techniques, CMOS mixed signal circuits, comparators, folded cascode, hardening-by-design, hardness by design, radiation hardening, single-event effects (SEEs), single-event transients (SETs), single-event upsets (SEUs), spice simulation.

A summary of the work carried out to characterize the absorption behavior of aqueous zirconium and hafnium species onto thermally grown silicon dioxide is presented. To understand the extent and nature of interaction, electrokinetic and adsorption measurements were carried out.

Background: Liver ischemia reperfusion (I/R) injury is a major complication of liver resection and transplantation. The cytokine release by activated Kuppfer cells (KCs) plays a central role and glycine inhibits [...]