Search

In this brief, we use the alpha power law model for MOS devices to reach a more accurate modeling of CMOS buffers in very deep submicrometer technologies. We derive alpha model parameters of a CMOS buffer for 90-, 65-, and 45-nm technologies using HSPICE simulations. By analytical efforts we find the output resistance of a minimum-size buffer and compare it with those extracted from HSPICE simulations. We propose a new model for the output resistance of a given-size buffer in any technology, which demonstrates 3% error on average as opposed to the conventional model. Also a new buffer resistance is proposed analytically and numerically to calculate the crosstalk for interconnect analysis applications. In addition, we propose a model for the transfer function zero generated by the gate-drain capacitances of MOS transistors, which cause the overshooting effect, and develop an accurate expression for modeling this phenomenon. As the final point, together with the input-to-output capacitance, the equivalent output resistors present a simple and accurate macromodel for the CMOS buffer. [ABSTRACT FROM PUBLISHER]

This paper reports the design, fabrication and characterization of a head-mounted, flexible, and ultralight optogenetic system that enables wireless delivery of light into the brains of awake and freely behaving animals. The project is focused on miniaturized design, light weight (2.7g), small volume, low cost (< 25 USD) and simple fabrication. The chip, the substrate material, the battery, and the micro light emitting diode (μLED) are commercially available. The device implementation consists of one step photolithography, soldering, and packaging along with Arduino programming. In vivo study is carried out where the battery-powered μLED stimulates the visual cortex of a rat with parameters that can be controlled wirelessly via a smart-phone user interface application. The efficacy of optical stimulation is validated using c-Fos as a report of light-evoked neuronal activity.