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[SOLVED] PSpice Error subcircuit node is floating

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WFriedrich

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Hello,
I have a simple circuit to test a varicap model in PSpice.
Inside the varicap model seems to be a floating node.
Any ideas how to fix this?
The circuit is this:

Varicap%20test.png

The varicap model is this:
Code: 
.SUBCKT VARICAP 1 2 CTRL
R1 1 3 1u
VC 3 4
EC 4 2 Value = { (1/v(ctrl))*v(int) }
GINT 0 INT Value = { I(VC) }
CINT INT 0 1
.ENDS

PSpice output with the error:
*Libraries:
* Profile Libraries :
* Local Libraries :
.LIB "../../../varicap.lib"
* From [PSPICE NETLIST] section of U:\cdssetup\OrCAD_PSpice/16.6.0/PSpice.ini file:

*Analysis directives:
.TRAN 0 100us 0
.OPTIONS ADVCONV
.PROBE64 V(alias(*)) I(alias(*)) W(alias(*)) D(alias(*)) NOISE(alias(*))
.INC "..\SCHEMATIC1.net"

**** INCLUDING SCHEMATIC1.net ****
* source VARICAPTEST
V_V1 N00130 0 5Vdc
R_R1 N00130 N00137 1k TC=0,0
V_V2 N00170 0 1uVdc
X_U1 N00137 0 N00170 VARICAP
R_R2 0 N00170 1G TC=0,0

**** RESUMING varicaptest.cir ****
.END

ERROR(ORPSIM-15142): Node X_U1.int is floating
Click to expand...
I think the internal node INT is driven only by a current source and might need a DC path (resistor) to GND.

Any ideas how to fix this would be greatly appreciated.
Thanks,
- Wolfgang.
 

The solution was the standard answer for floating notes (add a very high value resistor (100 Mega ohm or more) between that floating node and ground), just in PSpice SUBCKT syntax. The working model looks like this:

Code: 
.SUBCKT VARICAP2 1 2 CTRL
R1 1 3 1u
R2 2 INT 1G
VC 3 4
EC 4 2 Value = { (1/v(ctrl))*v(int) }
GINT 0 INT Value = { I(VC) }
CINT INT 0 1
.ENDS

Notice R2 is the high value resistor connected from INT (the internal node) to 2 (external node).

Cheers, Wolfgang.
 

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