Simplify worst-case PSpice simulations with customized measurement expressions

摘要

During IC design, worst-case simulations help designers account for variations in characteristics of PNP and NPN transistors and base and polysilicon resistors. These four-classes of devices alone produce more than 16 combinations of simulation conditions. To accommodate temperature variations, each combination undergoes simulation at -40, +27 (room temperature), and + 125℃, producing at least 48 series of data to analyze when simulations are complete. To help an IC designer evaluate simulated waveforms' characteristics, PSpice provides a library of ready-to-use, predefined measurements, including bandwidth, gain/phase margins, and more. PSpice also allows a designer to use predefined YatX and XatNthY measurements to measure a waveform's y value at a given x value - usually, time - and to find an x value that corresponds to the nth instance of a given y value (Reference 1).