Hello,

I'm trying to model a very basic non-inverting amplifier using a Burr-Brown OPA134 opamp using OrCAD PSpice A/D 10.0 Demo, freely available from OrCAD's website.

I have zipped my design and put it up on:

The model uses an OPA134, created by following the instructions at:

The model also uses a 1k and a 10k resistor for the feedback network and a VAC source (Vac = 1, Vdc = 0) as input to the non-inverting input of the opamp.

I have played around with the simulation of this circuit for a while now, but I keep getting the following (entire PSpice output file follows):

What could the problem be?

Chris

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******PSpice Lite (Jan 2003)

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*** ***

*** Profile: "SCHEMATIC1-preamp" [ C:\\ORCAD\\work\\preamp\\preamp-PSpiceFiles\\SCHEMATIC1\\preamp.sim ]**

**
********** CIRCUIT DESCRIPTION

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****** Creating circuit file "preamp.cir"

******WARNING: THIS AUTOMATICALLY GENERATED FILE MAY BE OVERWRITTEN BY SUBSEQUENT SIMULATIONS

*Libraries:

- Profile Libraries : ..INC "C:\ORCAD\work\preamp\preamp-PSpiceFiles\SCHEMATIC1\preamp\preamp_profile.inc"

- Local Libraries :

************ INCLUDING preamp_profile.inc ************ ..STMLIB ".\\preamp.stl"

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******RESUMING preamp.cir

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******..LIB "C:/orcad/orcad_10.0_demo/tools/pspice/library/eval.lib" ..LIB "C:/orcad/orcad_10.0_demo/tools/pspice/UserLib/opa134.lib"

- From [PSPICE NETLIST] section of C:\orcad\orcad_10.0_demo\tools\PSpice\PSpice.ini file: ..lib "nom.lib"

***Analysis directives: ..AC DEC 100 100 1000000 ..OPTIONS STEPGMIN ..PROBE V(alias(***)) I(alias(***)) W(alias(***)) D(alias(***)) NOISE(alias(***)) ..INC "..\\SCHEMATIC1.net"

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- source PREAMP V_V1 N08548 GND_POWER DC 0Vdc AC 1Vac V_V2 GND_POWER N092391 20Vdc R_R1 GND_POWER N08368 1k V_V3 N092720 GND_POWER 20Vdc R_R2 N08368 N08386 10k X_U1 N08548 N08368 N092720 N092391 N08386 OPA134

************ RESUMING preamp.cir ************ ..END

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******PSpice Lite (Jan 2003)

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*** Profile: "SCHEMATIC1-preamp" [ C:\\ORCAD\\work\\preamp\\preamp-PSpiceFiles\\SCHEMATIC1\\preamp.sim ]**

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********** Diode MODEL PARAMETERS

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X_U1.DX IS 800.000000E-18

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******PSpice Lite (Jan 2003)

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*** Profile: "SCHEMATIC1-preamp" [ C:\\ORCAD\\work\\preamp\\preamp-PSpiceFiles\\SCHEMATIC1\\preamp.sim ]**

**
********** Junction FET MODEL PARAMETERS

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X_U1.JX PJF VTO -1 BETA 1.010000E-03 IS 2.500000E-15

ERROR -- Convergence problem in bias point calculation

Last node voltages tried were:

NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE

(N08368)-10.00E+09 (N08386)-10.00E+09 (N08548)-10.00E+09 (X_U1.6) ..0044

(X_U1.7)-10.00E+09 (X_U1.8)-10.00E+09 (X_U1.9) 0.0000 (N092391)-10.00E+09

(N092720)-10.00E+09 (X_U1.10)-10.00E+09

(X_U1.11)-10.00E+09 (X_U1.12)-10.00E+09

(X_U1.53)-10.00E+09 (X_U1.54)-10.00E+09

(X_U1.90) -.0461 (X_U1.91) 40.0000

(X_U1.92) -40.0000 (X_U1.99)-10.00E+09

(GND_POWER)-10.00E+09

These voltages failed to converge:

V(N08548) = -10.00GV \\ -10.00GV V(GND_POWER) = -10.00GV \\ -10.00GV V(N092391) = -10.00GV \\ -10.00GV V(N08368) = -10.00GV \\ -10.00GV V(N092720) = -10.00GV \\ -10.00GV V(N08386) = -10.00GV \\ -10.00GV V(X_U1.11) = -10.00GV \\ -10.00GV V(X_U1.12) = -10.00GV \\ -10.00GV V(X_U1.7) = -10.00GV \\ -10.00GV V(X_U1.10) = -10.00GV \\ -10.00GV V(X_U1.99) = -10.00GV \\ -10.00GV V(X_U1.53) = -10.00GV \\ -10.00GV V(X_U1.54) = -10.00GV \\ -10.00GV V(X_U1.8) = -10.00GV \\ -10.00GV

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