sim-measure

name	sim-measure
description	Extract waveform measurements from Virtuoso simulation results. Use when measuring voltage, current, gm, gm/Id, bandwidth, settling time, or any simulation metric.
argument-hint	["measurement target","e.g. \"GBW and phase margin from AC\""]
allowed-tools	Bash(virtuoso *)

Measure Simulation Results

Extract metrics from completed simulations via virtuoso sim measure.

Usage

virtuoso sim measure --analysis <TYPE> --expr '<EXPRESSION>' [--expr '<EXPR2>'] --format json

DC operating point measurements

# Voltage at a node
virtuoso sim measure --analysis dcOp --expr 'value(VDC("/net1"))' --format json

# Drain current
virtuoso sim measure --analysis dcOp --expr 'value(IDC("/NM0/D"))' --format json

# Operating point parameter (gm, gds, vth, etc.)
virtuoso sim measure --analysis dcOp --expr 'value(getData("/NM0:gm" ?result "dcOpInfo"))' --format json
virtuoso sim measure --analysis dcOp --expr 'value(getData("/NM0:ids" ?result "dcOpInfo"))' --format json
virtuoso sim measure --analysis dcOp --expr 'value(getData("/NM0:vth" ?result "dcOpInfo"))' --format json

# Multiple measurements at once
virtuoso sim measure --analysis dcOp \
  --expr 'value(VDC("/net1"))' \
  --expr 'value(IDC("/NM0/D"))' \
  --expr 'value(getData("/NM0:gm" ?result "dcOpInfo"))' \
  --format json

Transient measurements

# Peak voltage
virtuoso sim measure --analysis tran --expr 'ymax(VT("/OUT"))' --format json

# Minimum voltage
virtuoso sim measure --analysis tran --expr 'ymin(VT("/OUT"))' --format json

# Crossing time (settling)
virtuoso sim measure --analysis tran --expr 'cross(VT("/OUT") 0.6 1 "rising")' --format json

# Value at specific time
virtuoso sim measure --analysis tran --expr 'value(VT("/OUT") 10e-6)' --format json

AC measurements

# Gain at DC
virtuoso sim measure --analysis ac --expr 'value(dB20(VF("/OUT")) 1)' --format json

# Unity-gain bandwidth
virtuoso sim measure --analysis ac --expr 'cross(dB20(VF("/OUT")) 0 1 "falling")' --format json

# Phase margin
virtuoso sim measure --analysis ac --expr 'value(phase(VF("/OUT")) cross(dB20(VF("/OUT")) 0 1 "falling"))' --format json

Available signal accessors

Function	Domain	Description
VDC("/node")	dc	DC voltage
IDC("/inst/term")	dc	DC current
VT("/node")	tran	Transient voltage
IT("/inst/term")	tran	Transient current
VF("/node")	ac	AC voltage (complex)
IF("/inst/term")	ac	AC current (complex)
getData("/inst:param" ?result "dcOpInfo")	dcOp	Operating point param

Waveform math functions

Function	Description
ymax(wave)	Maximum value
ymin(wave)	Minimum value
value(wave time)	Value at time/freq
cross(wave val n dir)	Time when wave crosses val
dB20(wave)	20*log10(magnitude)
phase(wave)	Phase in degrees
bandwidth(wave level)	-3dB bandwidth
integ(wave)	Integral over sweep range
rms(wave)	RMS value
average(wave)	Average value
delay(wave1 val1 edge1 wave2 val2 edge2 n)	Propagation delay
slewRate(wave pct1 pct2 dir)	Slew rate
settlingTime(wave final tol)	Settling time

Noise measurements

# Run noise analysis first
virtuoso sim run --analysis noise --start 10 --stop 100e3 --dec 20 --timeout 120

# Spot noise at 1kHz
virtuoso sim measure --analysis noise \
  --expr 'value(getData("/OUT" ?result "noise") 1e3)'

# Integrated noise (10Hz-100kHz)
virtuoso sim measure --analysis noise \
  --expr 'integ(getData("/OUT" ?result "noise") 10 100e3)'

Common amplifier measurements (complete recipe)

# === DC operating point ===
virtuoso sim run --analysis dc --param saveOppoint=t
virtuoso sim measure --analysis dcOp \
  --expr 'value(VDC("/OUT"))' \
  --expr 'value(IDC("/M1/D"))'

# === AC: gain, GBW, phase margin ===
virtuoso sim run --analysis ac --start 1 --stop 10e9 --dec 20
DC_GAIN=$(virtuoso sim measure --analysis ac --expr 'dB20(value(VF("/OUT") 1))' --format json | jq -r '.measures[0].value')
UGB=$(virtuoso sim measure --analysis ac --expr 'cross(dB20(VF("/OUT")) 0 1 "falling")' --format json | jq -r '.measures[0].value')
PM=$(virtuoso sim measure --analysis ac --expr 'value(phase(VF("/OUT")) cross(dB20(VF("/OUT")) 0 1 "falling")) + 180' --format json | jq -r '.measures[0].value')
echo "Gain=${DC_GAIN}dB  GBW=${UGB}Hz  PM=${PM}°"

# === Transient: slew rate, settling ===
virtuoso sim run --analysis tran --stop 20u
virtuoso sim measure --analysis tran \
  --expr 'slewRate(VT("/OUT") 10 90 "rising")' \
  --expr 'slewRate(VT("/OUT") 90 10 "falling")'