A practical system for reading out from linear, multi-level, selectorless Resistive Random Access Memory (RRAM) arrays based on a Trans-Impedance Amplifier (TIA) approach is presented and studied. SPICE simulation of the core of the system is performed in order to extract predicted sensitivity to error factors such as non-zero TIA offsets and access resistance. A physical implementation of the system is then tested on a small, 12 × 12 reference array and measured results show its ability to decode absolute resistive states in the range of 1 kΩ–220 kΩ within ≈ 11% tolerance.

In this paper, we present a compact model for silicon-on-insulator (SOI) laterally double diffused (LD) MOSFETs. The model is complete insofar as it uses no subcircuits, and is intended to predict device operation in all regions of bias. The device current is described by two main equations handling the MOS channel and the drift region, both of which are smooth and continuous in all operating regimes. Attention is also given to the modeling of inversion at the back oxide to ensure correct behavior is predicted for a source follower in power control applications ("high side operation"). A surface-potential-based formulation is used for the inversion/accumulation channel giving smooth transitions between different regions of operation, and care has been taken to ensure all expressions are smooth and infinitely differentiable to achieve the best possible convergence performance. Self (and coupled) heating effects exert a major influence over the behavior of power SOI devices, and these issues are incorporated in the model core in a consistent fashion. The model has been installed in a commercial SPICE-type circuit simulator and evaluated against individual devices and complete circuits fabricated in an industrial smart power SOI process. Accuracy is significantly improved with respect to the existing LDMOS models, and convergence behavior in switching and linear circuit simulations is comparable with industry standard models of this complexity.

A CMOS second-order lowpass active-RC filter with voltage input and current output is presented. The mechanisms of harmonic distortion generation within the active circuit is detailed, along with techniques for reducing the distortion in the design. Calculated distortion levels from the analysis, along with simulated distortion levels are presented, for filters designed in a 0.8 /spl mu/m CMOS process.>

A switched-current (SI) sigma-delta modulator for the direct digitisation of photodiode currents is described. The noise-shaping filter is implemented by an SI second generation grounded gate integrator, and a current driven regenerative comparator forms the single bit quantiser. Measured results are presented for an IC implemented in a 0.8 /spl mu/m standard 5 V digital CMOS process.>

A circuit simulation model is presented suitable for the design of analogue and digital SOS MOSFET integrated circuits. Both the drift and diffusion components of channel current are modeled, which are computed from the surface potentials at the drain and source ends of the channel. The surface potential function varies continuously from subthreshold to strong inversion allowing a smooth transition of device conductances and capacitances at the threshold voltage. Charge is conserved in the model formulation yielding reliable simulation results in transient analysis. The model has been implemented in the SPICE program, together with important extrinsic elements such as impact ionization current, pn-junction current and capacitances, and substrate resistance. The pn-junction current expression includes a physical formulation for the drain leakage current. The influence of temperature on device characteristics is included, making the model valid from /spl minus/55 to 125/spl deg/C. Simulation results are compared with measured dc device characteristics showing considerable improvement over bulk MOS models in predicting the drain conductance. In subthreshold, the model predicts the observed increase in inverse subthreshold slope with drain bias for n-channel devices. Transient simulations show that capacitive coupling from drain, gate and source nodes can strongly influence the floating substrate potential. The model has been successfully applied to the design of analogue SOS circuits.>