[quote userid="564258" url="~/cadence_technology_forums/f/custom-ic-design/56658/veriloga-module-in-a-crystal-oscillator-simulation-testbench-negatively-affects-simulation-parameters-for-oscillation/1388130#1388130"]I understand this from the Cadence documentation. My understanding, rightly or wrongly, is that the choice of the "gear2only" algorithm will utilize gear2 as the dominant algorithm and to a greater extent than specifying "gear2".[/quote] This is covered in A.3.3.7 (page 352) of Ken Kundert's A Designer's Guide to SPICE and Spectre . [quote userid="564258" url="~/cadence_technology_forums/f/custom-ic-design/56658/veriloga-module-in-a-crystal-oscillator-simulation-testbench-negatively-affects-simulation-parameters-for-oscillation/1388130#1388130"]I am also well aware of the numerical damping the algorithm provides. However, this is easily overcome by a sustaining amplifier and its resonator with a reasonably robust design.[/quote] Of course, but given that the oscillation was already being attenuated, gear2only will only make that worse. In general, gear2only often gives the best bang for the buck, but trapezoidal generally will give the best accuracy - but sometimes the presence of trapzoidal ringing can cause a bigger problem - so there's always a tradeoff. [quote userid="564258" url="~/cadence_technology_forums/f/custom-ic-design/56658/veriloga-module-in-a-crystal-oscillator-simulation-testbench-negatively-affects-simulation-parameters-for-oscillation/1388130#1388130"]If the Cadence algorithm reverts to a first-order integration algorithm in this case, I am surprised, but will accept your answer ![/quote] This is covered in section 4.2.1 and 4.2.2 of Ken's' book (pages 131 onwards). Andrew
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