A versatile design using OpAmp with Multiple Inputs

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A versatile design using Op-Amp with Multiple
Inputs

• ref. A student paper presented to IEEE region VI
  by Phil Vrbancic

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Op-Amp with 3-non-inverting and 3-inverting inputs
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Design Equations,
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Design Summary
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Design Sample Using Vrbancic technique
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The feedback input resistors,
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Use Single-pole OPAMP1 modelREF-
http//www.ecircuitcenter.com/Circuits/opmodel1/op
model1.htm at eCenter
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Single-pole OPAMP1 Subckt model
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Using WinSpice
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WinSpice netlist
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Run WinSpice
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Open Netlist OA_multi_SINE2a.cir
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Processing the netlist
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Result

• Verified
• Vo 5 (1v) 3 (1v) 2 (1v) (1v) 5v

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Open Netlist OA_multi_SINE2b.cir
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Result
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Using PSpice AD
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PSpice Netlist
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Run PSpice AD open netlist
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Simulate the netlist,
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No error,
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Add Trace
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Select variable V(OUT), then OK
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V(OUT)
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Using PSpice Schematics
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Schematic
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The Include file OPAMP1.lib
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V(out)
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Using SwCAD III
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SwCAD netlist same as PSpice
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Run SwCAD, open netlist
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Run Simulation
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Blank window
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Select Visible Traces under Plot Settings,
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Select V(out) from available variables,
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V(out)
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Using SwCAD schematic
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Create New Schematic
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Click Component
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Pop library of symbols,
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Double click Opamps,
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Select LTC 1-pole OA, must .lib opamp.sub
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Enter SPICE directive
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Final complete circuit
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Netlist of subckt opamp
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opamp.sub Attribute
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Fill up desired Transient analysis, OK
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Run simulate
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V(OUT)
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To use our own OPAMP1.lib Subckt
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First design a symbol for OPAMP1.lib
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Retrieve component, resistors rotates, enter
values
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Enter Value of symbol OPAMP2
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Result,
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OPAMP1 as schematic
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OPAMP1_sch points to Schematic
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Navigate Symbol Schematic
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Symbol OPAMP1_sch
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Complete circuit
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Complete 0A_mult_LTC_sch
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OA_multi_LTC_sch
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Symbol OPAMP_LTC_1pole_sch
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Schematic OPAMP_LTC_1pole_sch