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Overview
AFS full-spectrum
periodic noise analysis (pnoise) computes the noise of
periodically-driven circuits such as mixers, switched-capacitor
filters, phase detectors, charge pumps, and dividers. AFS full-spectrum
pnoise
analysis
is faster than AFS Transient Noise
for these types of circuits
with identical results and
provides additional diagnostic information such as noise source
contributions.
Benefits
- Always
nanometer SPICE accuracy
- Always
full spectrum - no need to specify
maxsideband
- 5x-10x
faster when RF tools use >100 sidebands
- Computes
total noise for every source
- Periodic
small signal analysis (PAC, PXF)
- Capacity
to handle post-layout circuits
Target
Applications
- >1
GHz,
nanometer-scale post-layout CMOS circuits
- Highly
non-lineard RF
circuits
- Complex
LNA +
mixer circuits, including switching mixers
- Power
amplifiers (digitally modulated and distributed PAs)
- Frequency
dividers with up to 12 bits
- Complete
transmit and
receive chains
PSS with >100K-Element Capacity
The
periodic steady-state (PSS) analysis is an efficient time-domain method
that uses the shooting method to calculate one steady-state period
accurately. AFS RF has
superior PSS
convergence that easily handles
circuits that are far too complex for any other tool – up to
100,000 elements.
Sidebands versus
Accuracy for Limited-Spectrum pnoise
The figure below gives a comparison of AFS
full-spectrum pnoise with limited-spectrum pnoise and harmonic balance
methods. Based on actual customer results, the plot shows that the
limited-spectrum results approach AFS
full-spectrum pnoise as the
number of sidebands or harmonics is increased. In practice for circuits
with sharp transitions such as switched-capacitor circuits or phase
detectors, the limited-spectrum method will not converge with the
number of sidebands required for an accurate result.
AFS RF Specifications
AFS RF
Analysis uses industry-standard netlists and models and is fully
integrated into the leading EDA design environment. It produces
standard output file formats and includes sophisticated post-processing
and analysis capabilities.
- Analyses:
- Periodic
analyses: PSS, pnoise, pac, pxf
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