VSD - Circuit Design & SPICE Simulations - Part 2

Create a Spice deck for a cmos inverter by building the netlist, defining substrate connectivity, assigning mosfet w/l and voltages, and naming nodes like out and zero for simulation.

Simulate a CMOS inverter in SPICE by modeling a MOS transistor, sweeping input from 0 to 2.5 V, and analyzing the DC transfer characteristics using a detailed model file.

Explore spice simulations to compare CMOS devices of different sizes and W/L ratios, analyze switching threshold Vm and switching point, and assess robustness of CMOS logic in buffers and inverters.

Derives an analytical expression for the switching threshold VM as a function of the p and n transistor W/L ratios, analyzing drain-current balance in velocity-saturation.

Develop and apply the analytical expression for (W/L)p and (W/L)n as functions of Vm, to set a switching threshold at half supply, and validate sizing with Spice simulations.

Explore static and dynamic CMOS inverter behavior through SPICE simulations, analyzing DC transfer characteristics, transition analysis, and rise/fall delays with a pulse input.

Explore static and dynamic simulation of a CMOS inverter as PMOS width increases, using SPICE to analyze DC transfer characteristics and rise/fall delays, and observe shifts in switching threshold.

Explore how CMOS inverters in clock networks affect delay, rise/fall symmetry, and area through sizing variations, fabrication tolerances, and STA concepts like noise margins.

Explore noise margin in CMOS circuits, analyzing how crosstalk noise and glitches affect logic gate switching, and examine ideal versus practical transfer characteristics with resistances and capacitances.

Explore noise margin voltage parameters in CMOS logic, showing how input and output voltages define high and low logic levels and the role of transfer slope in inverter behavior.

Explore the concept of noise margins in digital CMOS, defining input voltage ranges for logic high and low. Discuss undefined regions, glitches, cross-talk, and how margins ensure reliable logic detection.

Explore how increasing PMOS width affects CMOS noise margins, analyzing SPICE results and DC transfer curves to identify the negative-slope point and robust operation.

Explore smart SPICE simulations to analyze CMOS inverter behavior under power supply variations from 2.5 V to 0.5 V, using scripting and DC sweeps for low voltage aerospace scenarios.

Explore the advantages and disadvantages of CMOS at 2.5 versus 0.5 volts in SPICE simulations. Compare energy savings, gain, rise and fall times, and assess how low voltage affects performance.

Explore how etching during fabrication creates variation in diffusion areas, polysilicon gates, and transistor geometry, and how these distortions affect capacitance, with CMOS immunity discussed.

Analyze sources of variation focusing on oxide thickness in MOSFETs. Examine cross-sectional transistor views to see how nonuniform oxide thickness affects oxide capacitance and device current.

Explore smart SPICE simulations to assess CMOS inverter response to extreme device variations, sweeping PMOS and NMOS sizes from the smallest to largest values and analyzing DC transfer characteristics.

Explore how SPICE simulations reveal CMOS robustness against process variations, analyzing switching points, noise margins, and static versus dynamic behavior.