Development of a 5V Digital Cell Library for use with the Peregrine Semiconductor Silicon-on-Sapphire Process

The scope of the thesis work presented here is to develop a standard digital cell library operable at 5V of power supply and up to the temperatures of 125C using Peregrine 0.5m2 3.3V CMOS process. Peregrine 0.5m process was selected as a result of its availability via commercial foundry at moderate cost radiation and high temperature tolerant properties. Testing data was obtained showing no measurable gate tunneling at gate voltages below 8.5V and no source to drain avalanche below 5.5V ensuring safe operation below the 5V design corners of 5.5V. Device geometries are selected to meet drive current requirement of 1mA and acceptable Ion/Ioff ratios at high temperature. Layouts for cells, schematic, symbolic and abstract views were generated. Timing, power and area characterization data is realized in several formats compatible with Cadence and Synopsys synthesizer, place & route and simulation tools. A test chip for delay chains with single input and multi-input combinatorial gates were designed and fabricated as a part of the validation on silicon. Measured data at room temperature is well in agreement with SignalStorm's data. At 125C, delay chains performed faster in silicon by up to 25% as compared with simulated data obtained using typical model. Device characteristics for rn and rp device are obtained and percentage variations in their Id-Vd characteristics with models are calculated. Variation in test data for the test chip as compared to the simulated data is observed to be consistent with the device current variation plotted across process corners. Adherence of the targeted design specifications (from simulation) with the actual measured values verifies the cell library's functionality, timing and power parameters.School of Electrical & Computer Engineerin

Study of Neurological and Biochemical Manifestations in HIV Patients

Background & Aims: Nervous system involvement causes significant degree of morbidity in the patients with Human Immunodeficiency Virus (HIV) infection. At least 10% of the cases of Acquired Immune Deficiency Syndrome (AIDS) present with neurological symptoms and over the course of the illness symptomatic involvement of the central and peripheral nervous system has been found in 30 to 60% of the patients. Materials & Methods: This study included the patients with HIV disease presenting various neurological manifestations admitted into Departments of Medicine and Neurology. In all cases provisional diagnosis was made by taking detailed history and clinical examination. All the cases were subjected to investigations like CD4 count, CSF analysis, EEG, nerve conduction studies, and CT scan and MRI of brain and spinal cord to establish the etiology. Results: The predominant symptoms observed in the study were headache (70%) and fever (65%). Out of the 100 patients, 30 patients presented with seizures. Central nervous system tuberculosis is the underlying cause in 50% of the cases. Neck stiffness and positive kernig’s sign were seen in 55%. CSF analysis of the patients disclosed a picture suggestive of tuberculosis meningitis in 60%. The radiological evaluation in the form of CT or MRI brain showed lesions like cortical infarcts in 28%. Conclusion: The study disclosed tuberculosis of the CNS to be the major cause for seizures and other neurological disorders in HIV. Even though neurological manifestations can occur at any level of CD4 count, prognosis is bad if CD4 count is less than 200