Life After SPICE

I graduated among the last wave of students who really focused on circuit simulation at the University of California (UC), Berkeley. Those students included Tom Quarles, who wrote SPICE3 as a way of improving the underlying architecture of SPICE, and Jacob White, who explored new numerical algorithms such as waveform relaxation as a way of accelerating traditional SPICE transient analysis. These students, like most of the ones who preceded them, accepted the basic capabilities of SPICE and were working to improve them by making them faster, more accurate, and more robust. My work was a bit different; I focused on teaching the old dog new tricks. I tried to develop new analyses specifically tailored for designers of high-frequency circuits. In particular, I worked to develop methods for efficiently computing the steady-state response of a circuit. This work culminated in the development of a harmonic balance simulator that eventually formed the basis of the commercial microwave simulator from Hewlett Packard (now Agilent). After graduation, I went in another direction. I took the harmonic balance simulator I wrote as a student to Cadence and converted it to a general purpose SPlCE-like simulator. At the time HSPICE was the dominant commercial simulator for integrated circuits, and some of us at Cadence had aspirations of building a new simulator to replace it. I took the lessons I learned about simulator architecture from Tom Quarles and simulator algorithms from Jacob White and produced a new simulator named Spectre that was several times faster than HSPICE as well as being more accurate and more robust (actually, Jacob and I working together completed the first version in two weeks). Essentially, I took everything that had been learned since the development of SPICE2 and put it into Spectre. It was not enough.