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12.2. ANALOG MODELS
Limits:
Vector:
Vector_Bounds:
Null_Allowed:
PARAMETER_TABLE:
Parameter_Name:
Description:
Data_Type:
Default_Value:
Limits:
Vector:
Vector_Bounds:
Null_Allowed:
181
no
no
no
no
alpha
"model parameter 1"
real
0.0
no
no
beta
"model parameter 2"
real
1.0
no
no
Description: The memristor is a two-terminal resistor with memory, whose resistance depends
on the time integral of the voltage across its terminals. rmin and rmax provide the lower
and upper limits of the resistance, rinit is its starting value (no voltage applied so far).
The voltage has to be above a threshold vt to become effective in changing the resistance.
alpha and beta are two model parameters. The memristor code model is derived from a
SPICE subcircuit published in [23].
Example SPICE Usage:
amen 1 2 memr
.model memr memristor (rmin=1k rmax=10k rinit=7k
+ alpha=0 beta=2e13 vt=1.6)
12.2.27
2D table model
NAME_TABLE:
C_Function_Name:
Spice_Model_Name:
Description:
PORT_TABLE:
Port_Name:
PARAMETER_TABLE:
Parameter_Name:
Description:
Data_Type:
Default_Value:
Limits:
Vector:
Vector_Bounds:
Null_Allowed:
PARAMETER_TABLE:
Parameter_Name:
Description:
Data_Type:
Default_Value:
cm_table2D
table2D
"2D table model"
inx
iny
order
"order"
int
3
no
yes
verbose
"verbose"
int
0
no
yes
offset
"offset"
real
0.0
gain
"gain"
real
1.0
out Description:
182
CHAPTER 12. MIXED-MODE AND BEHAVIORAL MODELING WITH XSPICE
Limits:
Vector:
Vector_Bounds:
Null_Allowed:
PARAMETER_TABLE:
Parameter_Name:
Description:
Data_Type:
Default_Value:
Limits:
Vector:
Vector_Bounds:
Null_Allowed:
no
yes
no
yes
file
"file name"
string
"2D-table-model.txt"
no
yes
Description: The 2D table model reads a matrix from file "file name" (default 2D-table-model.txt)
which has x columns and y rows. Each x,y pair, addressed by inx and iny, yields an output
value out. Linear interpolation is used for out, eno (essentially non oscillating) interpolation for its derivatives. Parameters offset (default 0) and gain (default 1) modify the
output table values according to offset + gain*out. Parameter order (default 3) influences
the calculation of the derivatives. Parameter verbose (default 0) yields test outputs, if set
to 1 or 2. The table format is shown below. Be careful to include the data point inx = 0,
iny = 0 into your table, because ngspice uses to start there during op calculation. x horizontal and y vertical adress values have to increase monotonically. The usage example
consists of two input voltages referenced to ground and a current source output with two
floating nodes.
Table Example:
* table source
* number of columns (x)
8
* number of rows (y)
9
* x horizontal (column) address values (real numbers)
-1 0 1 2 3 4 5 6
* y vertical (row) address values (real numbers)
-0.6 0 0.6 1.2 1.8 2.4 3.0 3.6 4.2
* table with output data (horizontally addressed by x, vertically by y)
1 0.9 0.8 0.7 0.6 0.5 0.4 0.3
1 1 1 1 1 1 1 1
1 1.2 1.4 1.6 1.8 2 2.2 2.4
1 1.5 2 2.5 3 3.5 4 4.5
1 2 3 4 5 6 7 8
1 2.5 4 5.5 7 8.5 10 11.5
1 3 5 7 9 11 13 15
1 3.5 6 8.5 11 13.5 16 18.5
1 4 7 10 13 16 19 22
Example SPICE Usage:
atab inx iny %id(out1 out2) tabmod
.model tabmod table2d (offset=0.0 gain=1 order=3 file="table-simple.txt")
12.2. ANALOG MODELS
12.2.28
183
3D table model
NAME_TABLE:
C_Function_Name:
Spice_Model_Name:
Description:
PORT_TABLE:
Port_Name:
Description:
Direction:
Default_Type:
Allowed_Types:
Vector:
Vector_Bounds:
Null_Allowed:
PORT_TABLE:
Port_Name:
Description:
Direction:
Default_Type:
Allowed_Types:
Vector:
Vector_Bounds:
Null_Allowed:
PARAMETER_TABLE:
Parameter_Name:
Description:
Data_Type:
Default_Value:
Limits:
Vector:
Vector_Bounds:
Null_Allowed:
PARAMETER_TABLE:
Parameter_Name:
Description:
Data_Type:
Default_Value:
Limits:
Vector:
Vector_Bounds:
Null_Allowed:
PARAMETER_TABLE:
Parameter_Name:
Description:
Data_Type:
Default_Value:
Limits:
Vector:
cm_table3D
table3D
"3D table model"
inx
"inputx"
in
v
[v,vd,i,id,vnam]
no
no
iny
"inputy"
in
v
[v,vd,i,id,vnam]
no
no
out
"output"
out
i
[v,vd,i,id]
no
no
order
"order"
int
3
no
yes
offset
"offset"
real
0.0
no
yes
verbose
"verbose"
int
0
no
yes
gain
"gain"
real
1.0
no
yes
file
"file name"
string
"3D-table-model.txt"
no
inz
"inputz"
in
v
[v,vd,i,id,vnam]
no
no
184
CHAPTER 12. MIXED-MODE AND BEHAVIORAL MODELING WITH XSPICE
Vector_Bounds:
Null_Allowed:
yes
Description: The 3D table model reads a matrix from file "file name" (default 3D-tablemodel.txt) which has x columns, y rows per table and z tables. Each x,y,z triple, addressed by inx, iny, and inz yields an output value out. Linear interpolation is used for
out, eno (essentially non oscillating) interpolation for its derivatives. Parameters offset
(default 0) and gain (default 1) modify the output table values according to offset +
gain*out. Parameter order (default 3) influences the calculation of the derivatives. Parameter verbose (default 0) yields test outputs, if set to 1 or 2. The table format is shown
below. Be careful to include the data point inx = 0, iny = 0, inz = 0 into your table, because
ngspice uses to start there during op calculation. x horizontal, y vertical, and z table adress
values have to increase monotonically. The usage example simulates a NMOS transistor
with independent drain, gate and bulk nodes, referenced to source. Parameter gain may
be used to emulate transistor width, with respect to the table transistor.
Table Example:
* 3D table for nmos bsim 4, W=10µm, L=0.13µm
*x
39
*y
39
*z
11
*x (drain voltage)
-0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 ...
*y (gate voltage)
-0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 ...
*z (substrate voltage)
-1.8 -1.6 -1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2
*table -1.8
-4.50688E-10 -4.50613E-10 -4.50601E-10 -4.50599E-10 ...
-4.49622E-10 -4.49267E-10 -4.4921E-10 -4.49202E-10 ...
-4.50672E-10 -4.49099E-10 -4.48838E-10 -4.48795E-10 ...
-4.55575E-10 -4.4953E-10 -4.48435E-10 -4.48217E-10 ...
...
*table -1.6
-3.10015E-10 -3.09767E-10 -3.0973E-10 -3.09724E-10 ...
-3.09748E-10 -3.08524E-10 -3.08339E-10 -3.08312E-10 ...
...
*table -1.4
-2.04848E-10 -2.04008E-10 -2.03882E-10 ...
-2.07275E-10 -2.03117E-10 -2.02491E-10 ...
...
Example SPICE Usage:
amos1 %vd(d s) %vd(g s) %vd(b s) %id(d s) mostable1
.model mostable1 table3d (offset=0.0 gain=0.5 order=3
+ verbose=1 file="table-3D-bsim4n.txt")