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Subsections
ACS behavioral modeling functions are an extension of the Spice source
time dependent values.
They apply to all elements (primitive components).
All accept either Spice compatible order dependent parameters, or
easier keyword=value notation.
Some of the Hspice nonlinear functions are provided.
The syntax is identical for all supported components. This might
force it to be a little different from Hspice, even where
functionality is the same.
Time dependent functions are voltage or current as a function of time.
They are mostly Spice compatible, with extensions.
Nonlinear transfer functions use time as the independent variable.
Some may not make sense, but they are there anyway.
Time dependent functions are capacitance or inductance as a function
of time. They are voltage/current conserving, not charge/flux
conserving.
Nonlinear transfer functions are charge or flux as a function of input
(voltage or current). THIS IS NOT COMPATIBLE WITH HSPICE. ACS will
accept the HSPICE syntax, but it is interpreted different. Charge and
flux are conserved, and can be probed.
Time dependent functions are resistance or conductance as a function
of time.
Nonlinear transfer functions are current or voltage as a function of
input (voltage or current). Resistors define voltage as a function of
current. Conductances define current as a function of voltage.
Time dependent functions are gain (v/v, transconductance, etc)
function of time.
Nonlinear transfer functions are output (voltage or current) as a
function of input (voltage or current).
- COMPLEX
- Complex (re, im) value.
- EXP
- Spice Exp source. (time dependent value).
- GENERATOR
- Value from Generator command.
- POLY
- Polynomial (Spice style).
- POSY
- Posynomial (Like poly, non-integer powers).
- PULSE
- Spice Pulse source. (time dependent value).
- PWL
- Piece-wise linear.
- SFFM
- Spice Frequency Modulation (time dependent value).
- SIN
- Spice Sin source. (time dependent value).
- TANH
- Hyperbolic tangent transfer function.
These parameters are available with all functions. Some may not make
sense in some cases, but they are available anyway.
- Bandwidth = x
- AC analysis bandwidth.
(Default = infinity.) The transfer function is frequency dependent,
with a 3 DB point at this frequency. There is frequency dependent
phase shift ranging from 0 degrees at low frequencies to 90 degrees at
high frequencies. The phase shift is 45 degrees at the specified
frequency. AC ANALYSIS ONLY.
- Delay = x
- AC analysis delay. (Default = 0.)
The signal is delayed by x seconds, effectively by a frequency
dependent phase shift. AC ANALYSIS ONLY.
- Phase = x
- AC analysis phase. (Default = 0.)
A fixed phase shift is applied. This is primarily intended for
sources, but applies to all elements. AC ANALYSIS ONLY.
- IOffset = x
- Input offset. (Default = 0.)
A DC offset is added to the ``input'' of the element, before
evaluating the function.
- OOffset = x
- Output offset. (Default = 0.)
A DC offset is added to the ``output'' of the element, after
evaluating the function.
- Scale = x
- Transfer function scale factor.
(Default = 1.) The transfer function is multiplied by a constant.
- TNOM = x
- Nominal temperature. (Default = .option TNOM)
The nominal values apply at this temperature.
- TC1 = x
- First order temperature coefficient.
(Default = 0.)
- TC2 = x
- Second order temperature coefficient.
(Default = 0.)
- IC = x
- Initial condition. An initial value, to
force at time=0. The actual parameter applied depends on the
component. (Capacitor voltage, inductor current. All others ignore
it.) You must use the ``UIC'' option for it to be used.
Temperature adjustments and scaling use the following formula:
value *= _scale * (1 + _tc1*tempdiff
+ _tc2*tempdiff*tempdiff)
where tempdiff is t - _tnom.
Next: COMPLEX: Complex value
Up: Behavioral modeling
Previous: Conditionals
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Al Davis
2000-09-04