Cadence 5 (IC5141) vs Cadence 6 (IC615, IC616, IC617, IC618)
Three level of products applied to Virtuoso schematic and layout: L, XL, GXL
L - basic tools, polygon editor
XL - interconnection information
GXL - automatic tools: placement, routing, etc
PS: cadence uses 'tokens' for licensing (L might use 1 token, XL 3 tokens, GXL 9 tokens). Better stick with XL when possible.
SOC Encounter
support HDL program ( verilog, VHDL, verilog-a, VHDL-a, system-C, etc)
digital RTL to GDSII program including floorplanning, clock distribution, power planning, place and route (PR), analysis (timing, power, interconnect, signal integrity, etc), design for manufacturing (DFM).
Virtuoso schematic and layout
ADE L, XL
ADE Explorer and Assemble
Supported Analysis
Transient: time-domain analysis
measure the output time-waveform for given input time-signals
any circuits can use TRAN to simulate but can never be completely verified
DC/AC
belong to steady-state analysis
DC analysis is to find the DC steady-state response of a circuit
AC analysis is to calculate the steady-state response to a small-signal, sinusoidal perturbation
both can be used for ones with linear, time-invariant behaviors and a frequency-domain transfer function completely describing the functional behavior (filtering, narrow-band amplification)
Noise
Stability
Periodic Steady-State (PSS) Analysis
Supported circuits: mixers and oscillators
find a steady-state response of a periodic circuit and as an extension of DC analysis to periodic circuits
have conversion issues without careful settings
convergence problems are usually the designers' faults - the circuit isn't really periodic! That means the entire circuit must be perfectly periodic at the prescribed fundamental frequency
some parts has longer periods
full description by typing command: 'unix > spectre -h pss '
Two methods:
Harmonic Balance: frequency-domain method
(accuracy is limited by the number of harmonics used - not suitable for simulating strongly nonlinear responses)
Shooting Newton: time-domain method
(not need to choose the number of harmonics, however, the time step should be find enough to simulate the max frequency AC response - can't handle frequency-domain models directly)
PAC: periodic AC
PNOISE: periodic noise
PSTB: periodic stability
performs stability analysis for circuits with periodically time-varying operating points. PSTB is the periodic equivalent of linear stability (STB) analysis in that it calculates the small-signal loop gain, gain margin, and phase margin around a periodic operating point.
Spectre
spectre is cadence's version of SPICE
a conversion tool (spp) needs to convert SPICE to Spectre models
SpectreRF
Hspice/HspiceD
UltraSim