Use independent source element statements to specify DC, AC, transient, and mixed independent voltage and current sources. Some types of analysis use the associated analysis sources. For example, in a DC analysis, if both DC and AC sources are specified in one independent source element statement, the AC source is taken out of the circuit for the DC analysis. If an independent source is specified for an AC, transient, and DC analysis, transient sources are removed for the AC analysis and DC sources are removed after the performance of the operating point. Initial transient value always overrides the DC value.
Voltage sources need not be grounded. Positive current is assumed to flow from the positive node through the source to the negative node. A positive current source forces current to flow out of the N+ node through the source and into the N- node.
You can use parameters as values in independent sources. Do not identify these parameters using any of the following reserved keywords:
AC ACI AM DC EXP PE PL
PU PULSE PWL R RD SFFM SIN
The general syntax for including an independent source in a Star-Hspice netlist is:
Vxxx n+ n- <<DC=> dcval> <tranfun> <AC=acmag, <acphase>>
or
Iyyy n+ n- <<DC=> dcval> <tranfun> <AC=acmag, <acphase>>
+ <M=val>
The arguments are defined as follows:
Voltage source VX has a 5 volt DC bias, and the positive terminal is connected to node 1while the negative terminal is grounded.
VX 1 0 5V
Voltage source VB has a DC bias specified by the parameter `VCC', and the positive terminal is connected to node 2 while the negative terminal is grounded.
VB 2 0 DC=VCC
Voltage source VH has a 2 volt DC bias, a 1 volt RMS AC bias with 90 degree phase offset, and the positive terminal is connected to node 3 while the negative terminal is connected to node 6.
VH 3 6 DC=2 AC=1,90
Current source IG has a time-varying response given by the piecewise-linear relationship with 1 milliamp at time=0 and 5 milliamps at 25 milliseconds, and the positive terminal is connected to node 8 while the negative terminal is connected to node 7.
IG 8 7 PL(1MA 0S 5MA 25MS)
Voltage source VCC has a DC bias specified by the parameter `VCC', and a time-varying response given by the piecewise-linear relationship with 0 volts at time=0, `VCC' from 10 to 15 nanoseconds and back to 0 volts at 20 nanoseconds. The positive terminal is connected to node in while the negative terminal is connected to node out. The operating point for this source will be determined without the DC value (that is, it will be 0 volts).
VCC in out VCC PWL 0 0 10NS VCC 15NS VCC 20NS 0
Voltage source VIN has a 0.001 volt DC bias, a 1 volt RMS AC bias, and a sinusoidal time-varying response from 0 to 1 volts with a frequency of 1 megahertz. The positive terminal is connected to node 13 while the negative terminal is connected to node 2.
VIN 13 2 0.001 AC 1 SIN (0 1 1MEG)
Current source ISRC has a 1/3 amp RMS AC response with a 45-degree phase offset and a frequency modulated time-varying response with variation from 0 to 1 volts, a carrier frequency of 10 kHz, a signal frequency of 1 kHz and a modulation index of 5. The positive terminal is connected to node 23 while the negative terminal is connected to node 21.
ISRC 23 21 AC 0.333 45.0 SFFM (0 1 10K 5 1K)
Voltage source VMEAS has a 0 volt DC bias, and the positive terminal is connected to node 12 while the negative terminal is connected to node 9.
VMEAS 12 9
For a DC source, you can specify the DC current or voltage in different ways:
V1 1 0 DC=5V
V1 1 0 5V
I1 1 0 DC=5mA
I1 1 0 5mA
The first two examples specify a DC voltage source of 5 V connected between node 1 and ground. The third and fourth examples specify a 5 mA DC current source between node 1 and ground. The direction of current in both sources is from node 1 to ground.
AC current and voltage sources are impulse functions used for an AC analysis. Specify the magnitude and phase of the impulse with the AC keyword.
V1 1 0 AC=10V,90
VIN 1 0 AC 10V 90
The above two examples specify an AC voltage source with a magnitude of 10 V and a phase of 90 degrees. Specify the frequency sweep range of the AC analysis in the .AC analysis statement. The AC or frequency domain analysis provides the impulse response of the circuit.
For transient analysis, you can specify the source as a function of time. The functions available are pulse, exponential, damped sinusoidal, single frequency FM, and piecewise linear function.
Mixed sources specify source values for more than one type of analysis. For example, you can specify a DC source specified together with an AC source and transient source, all of which are connected to the same nodes. In this case, when specific analyses are run, Star-Hspice selects the appropriate DC, AC, or transient source. The exception is the zero-time value of a transient source, which overrides the DC value, and is selected for operating-point calculation for all analyses.
VIN 13 2 0.5 AC 1 SIN (0 1 1MEG)
The above example specifies a DC source of 0.5 V, an AC source of 1 V, and a transient damped sinusoidal source, each of which are connected between nodes 13 and 2. For DC analysis, the program uses zero source value since the sinusoidal source is zero at time zero.
Star-Hspice Manual - Release 2001.2 - June 2001