C Model-Capacitor Model

C_Model:Capacitor Model

The SPICE C and Spectre capacitor models are translated to the ADS C_Model. For translation information on the capacitor device, refer to the Cxxxxxxx for SPICE and the Capacitor Device for Spectre.

For more information on the ADS model, place the model in a schematic and choose Edit > Component > Edit Component Parameters to view the model parameters. You can also click Help in the component editor dialog box for additional information.

Example SPICE Command Line:

.model Cmodel1 c CJ=5e-5

Example Spectre Command Line:

model proc\_cap capacitor c=2u tc1=1.2e-8 tnom=25 w=4u l=4u cjsw=2.4e-10

SPICE and Spectre Dialect and Netlist Syntax:

Spice2/3:	.model mname c [param= value]*
PSpice:	.model mname cap [param= value]*
HSpice:	.model mname c [param= value]*
Spectre:	model mname capacitor [param= value]*

ADS Netlist Syntax:

model mname C_Model [param= value]*

ADS Schematic Symbol:

Model Parameters:

For information on parameter format, refer to Using Parameter Mapping Tables to Understand a Translation.

ADS	Default	Unit	Spice2/3	PSpice	HSpice	Spectre
C	1e-12 (1 pF)	F	C	CAP	CAP (0 F)	c 0.0 F
Cj	0.0	F/m ²	x	-	COX (see comment)	cj 0.0 F/m ²
Cjsw	0.0	F/m	x	-	CAPSW	cjsw 0.0 F/m
Length		m	-	-	x	l 0.0 m
Width		m	DEFW=1e-6	-	x	w 0.0 m
Narrow	0.0	m	x	-	DEL	etch 0.0 m
Coeffs	list(0,0,...)	1/V, 1/V ² , ...	-	-	-	coeffs [0 0 ...]
Tnom	25	°C	-	-	TREF (°C)	tnom set by options °C
Trise	0.0	°C	-	-	-	trise 0.0°C
TC1	0.0	1/°C	-	(0°C ^-1 )	x	tc1 0.0 1/°C
TC2	0.0	1/°C ²	-	(0°C ^-2 )	x	tc2 0.0 1/°C ²
Scale	1		-	-	-	scalec 1

SPICE Comments:

If the Cj parameter is not given, it will be calculated by the translator using the di and thick parameters. ADS does not have di or thick parameters.
If cox is non-zero, Cj=cox. Otherwise, Cj=cj_eqn which is calculated as follows:

If the Scale parameter is given, the capacitance is set to value * scale .
When the referenced model is not present in the netlist, the netlist translator fails to recognize the resistor model in the following syntax:
c1 1 2 cmodel
The translator assumes that it is a variable name for the capacitance value. To correct your imported schematic, manually move the model name to the parameter Model. To correct the ADS Netlist, use the following netlist syntax:
cmodel:c1 1 2 [param=value]*
To prevent the problem, ensure that the netlist translator has access to a model statement so it can verify that "cmodel" is a model. This can be a dummy statement without parameters such as the following:
.model cmodel C
or a .INC reference to an include file with the model available.