SpectreRF
Encyclopedia
SpectreRF is an option to the Spectre Circuit Simulator
from Cadence Design Systems
. It adds a series of analyses that are particularly useful for RF circuits to the basic capabilities of Spectre. SpectreRF was first released in 1996 and was notable for three reasons. First, it was arguably the first RF simulator in that it was the first to be designed for large bipolar and CMOS RF circuits; it used shooting methods as its base algorithm; and it pioneered the use of Krylov subspace
methods . The use of shooting methods gave SpectreRF remarkable robustness and the Krylov methods gave it capacity that was roughly 100 times greater than existing simulators at the time. Previously such simulators were designed to simulate very small GaAs integrated circuits and hybrids. These simulators were based on harmonic balance
and could reliably simulate circuits with tens of transistors whereas SpectreRF could simulate circuits with thousands of transistors.
SpectreRF added the Periodic Steady State and Periodic small-signal analyses to Spectre. The Periodic Steady-State or PSS analysis directly computed the periodic steady-state response of a circuit. The periodic small-signal analyses use the periodic steady-state solution as a periodically time-varying operating point and linearize the circuit about that operating point and then computes the response of the circuit to small perturbation sources. Effectively they build a periodically time-varying linear model of the circuit. This is significant as periodically time-varying linear models, unlike the time-invariant linear models used by the traditional small-signal analyses (AC and noise) exhibit frequency conversion. SpectreRF pioneered a variety of periodic small-signal analyses, including aeriodic AC (pac), periodic noise (pnoise), periodic transfer function (pxf), periodic s-parameter (psp) and periodic stability (pstb).
After its introduction, SpectreRF quickly became the dominant simulator for RF integrated circuits, and was instrumental in establishing Spectre as the most popular circuit simulator for integrated circuits. Eventually the dominance of SpectreRF faded as the use of Krylov subspace methods propagated to other simulators, particularly those based on harmonic balance. SpectreRF now provides harmonic balance in addition to shooting methods, both of which are accelerated using Krylov subspace methods.
SpectreRF was developed by Ken Kundert
, Jacob White
, and Ricardo Telichevesky.
Spectre Circuit Simulator
Spectre is a SPICE-class circuit simulator. It provides the basic SPICE analyses and component models. It also supports the Verilog-A modeling language...
from Cadence Design Systems
Cadence Design Systems
Cadence Design Systems, Inc is an electronic design automation software and engineering services company, founded in 1988 by the merger of SDA Systems and ECAD, Inc...
. It adds a series of analyses that are particularly useful for RF circuits to the basic capabilities of Spectre. SpectreRF was first released in 1996 and was notable for three reasons. First, it was arguably the first RF simulator in that it was the first to be designed for large bipolar and CMOS RF circuits; it used shooting methods as its base algorithm; and it pioneered the use of Krylov subspace
Krylov subspace
In linear algebra, the order-r Krylov subspace generated by an n-by-n matrix A and a vector b of dimension n is the linear subspace spanned by the images of b under the first r powers of A , that is,...
methods . The use of shooting methods gave SpectreRF remarkable robustness and the Krylov methods gave it capacity that was roughly 100 times greater than existing simulators at the time. Previously such simulators were designed to simulate very small GaAs integrated circuits and hybrids. These simulators were based on harmonic balance
Harmonic balance
Harmonic balance is a method used to calculate the steady-state response of non-linear differential equations, and is mostly applied to electrical circuits...
and could reliably simulate circuits with tens of transistors whereas SpectreRF could simulate circuits with thousands of transistors.
SpectreRF added the Periodic Steady State and Periodic small-signal analyses to Spectre. The Periodic Steady-State or PSS analysis directly computed the periodic steady-state response of a circuit. The periodic small-signal analyses use the periodic steady-state solution as a periodically time-varying operating point and linearize the circuit about that operating point and then computes the response of the circuit to small perturbation sources. Effectively they build a periodically time-varying linear model of the circuit. This is significant as periodically time-varying linear models, unlike the time-invariant linear models used by the traditional small-signal analyses (AC and noise) exhibit frequency conversion. SpectreRF pioneered a variety of periodic small-signal analyses, including aeriodic AC (pac), periodic noise (pnoise), periodic transfer function (pxf), periodic s-parameter (psp) and periodic stability (pstb).
After its introduction, SpectreRF quickly became the dominant simulator for RF integrated circuits, and was instrumental in establishing Spectre as the most popular circuit simulator for integrated circuits. Eventually the dominance of SpectreRF faded as the use of Krylov subspace methods propagated to other simulators, particularly those based on harmonic balance. SpectreRF now provides harmonic balance in addition to shooting methods, both of which are accelerated using Krylov subspace methods.
SpectreRF was developed by Ken Kundert
Ken Kundert
Kenneth S. Kundert is an engineer that is notable for his work in the area of Electronic Design Automation . He studied electrical engineering at the University of California, Berkeley under professors Alberto Sangiovanni-Vincentelli and Robert Meyer and received his doctorate in 1989. During this...
, Jacob White
Jacob K. White
Jacob K. White is the Cecil H. Green Professor of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology. He researches fast numerical algorithms for simulation, particularly the simulation of circuits...
, and Ricardo Telichevesky.