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Simulators >> Circuit Simulators >> How ADE computes outputs
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Message started by unevb on Jun 29^th, 2010, 4:38pm

Title: How ADE computes outputs
Post by unevb on Jun 29^th, 2010, 4:38pm

Simulator : Cadence Spectre
Using Monte Carlo tool in the Virtuoso Analog Design Environment

I am trying to find the offset voltage of an analog comparator by keeping one input (INM) at common mode voltage and applying a ramp to the other input (INP). Using monte carlo tool to do multiple iterations

I run a transient simulation

I first measure the time at while the output (compout) crosses Vdd/2 (0.6)
Tcross = cross(VT("/compout") 0.6 1 "rising" nil nil)

finally I would like the use value at INP at Tcross to find the threshold point of the circuit using

IN_thresh = value(VT("/vinp") Tcross)

But this does not work because it appears the outputs are not evaluated sequentially! and the value of Tcross is not available when the tool tries to compute IN_thresh. Any work around for this?