Current Dependent Current Sources -- F Elements
F Element syntax statements are described in the following paragraphs. The parameter definitions follow.
Current Controlled Current Source (CCCS)
Syntax
Linear
Fxxx n+ n- <CCCS> vn1 gain <MAX=val> <MIN=val> <SCALE=val> <TC1=val>
+ <TC2=val> <M=val> <ABS=1> <IC=val>
Polynomial
Fxxx n+ n- <CCCS> POLY(NDIM) vn1 <... vnndim> <MAX=val> <MIN=val> + <TC1=val> <TC2=val> <SCALE=vals> <M=val> <ABS=1> P0 <P1...>
+ <IC=vals>
Piecewise Linear
Fxxx n+ n- <CCCS> PWL(1) vn1 <DELTA=val> <SCALE=val><TC1=val> <TC2=val>
+ <M=val> x1,y1 ... x100,y100 <IC=val>
Multi-Input Gates
Fxxx n+ n- <CCCS> gatetype(k) vn1, ... vnk <DELTA=val> <SCALE=val> <TC1=val>
+ <TC2=val> <M=val> <ABS=1> x1,y1 ... x100,y100 <IC=val>
Delay Element
Fxxx n+ n- <CCCS> DELAY vn1 TD=val <SCALE=val> <TC1=val><TC2=val>
+ NPDELAY=val
Parameter Definitions
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ABS
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Output is absolute value if ABS=1.
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CCCS
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Keyword for current controlled current source. Note that CCCS is a reserved word and should not be used as a node name.
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DELAY
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Keyword for the delay element. The delay element is the same as a current controlled current source except it is associated by a propagation delay TD. This element facilitates the adjustment of propagation delay in the macromodel process.
Note:
DELAY is a reserved word and should not be used as a node name.
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DELTA
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Used to control the curvature of the piecewise linear corners. The parameter defaults to 1/4 of the smallest breakpoint distances. The maximum is limited to 1/2 of the smallest breakpoint distances.
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Fxxx
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Current controlled current source element name. The parameter must begin with an "F", followed by up to 1023 alphanumeric characters.
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gain
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Current gain
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gatetype(k)
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Can be one of AND, NAND, OR, or NOR. (k) represents the number of inputs of the gate. The x's and y's represent the piecewise linear variation of output as a function of input. In the multi-input gates, only one input determines the state of the output. The above keyword names should not be used as a node name.
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IC
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Initial condition: the initial estimate of the value(s) of the controlling current(s) in amps. If IC is not specified, the default=0.0.
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M
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Number of element in parallel
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MAX
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Maximum output current value. The default is undefined and sets no maximum value.
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MIN
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Minimum output current value. The default is undefined and sets no minimum value.
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n+/-
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Positive or negative controlled source connecting nodes
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NDIM
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Polynomial dimensions. If POLY(NDIM) is not specified, a one-dimensional polynomial is assumed. NDIM must be a positive number.
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NPDELAY
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Sets the number of data points to be used in delay simulations. The default value is the larger of 10 or the smaller of TD/tstep and tstop/tstep.
That is,
The values of tstep and tstop are specifed in the .TRAN statement.
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P0, P1 ...
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When one polynomial coefficient is specified, Star-Hspice assumes it to be P1 (P0=0.0) and the source is linear. When more than one polynomial coefficient is specified, the source is nonlinear, and P0, P1, P2 ... represent them.
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POLY
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Polynomial keyword function
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PWL
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Piecewise linear keyword function
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SCALE
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Element value multiplier
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TC1,TC2
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First and second order temperature coefficients. The SCALE is updated by temperature:
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TD
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Time delay keyword
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vn1 ...
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Names of voltage sources through which the controlling current flows. One name must be specified for each dimension.
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x1,...
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Controlling current through vn1 source. The x values must be in increasing order.
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y1,...
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Corresponding output current values of x
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Example
F1 13 5 VSENS MAX=+3 MIN=-3 5
The above example describes a current controlled current source connected between nodes 13 and 5. The current that controls the value of the controlled source flows through the voltage source named VSENS (to use a current controlled current source, a dummy independent voltage source is often placed into the path of the controlling current). The defining equation is:
The current gain is 5, the maximum current flow through F1 is 3 A, and the minimum current flow is -3 A. If I(VSENS) = 2 A, I(F1) would be set to 3 amps and not 10 amps as would be suggested by the equation. A user-defined parameter can be specified for the polynomial coefficient(s), as shown below.
.PARAM VU = 5
F1 13 5 VSENS MAX=+3 MIN=-3 VU
The next example describes a current controlled current source with the value:
I(F2)=1e-3 + 1.3e-3 · I(VCC)
F2 12 10 POLY VCC 1MA 1.3M
Current flow is from the positive node through the source to the negative node. The direction of positive controlling current flow is from the positive node through the source to the negative node of vnam (linear), or to the negative node of each voltage source (nonlinear).
Fd 1 0 DELAY vin TD=7ns SCALE=5
The above example is a delayed current controlled current source.
Filim 0 out PWL(1) vsrc -1a,-1a 1a,1a
The final example is a piecewise linear current controlled current source.
Star-Hspice Manual - Release 2001.2 - June 2001
