Op Amp Builder - Level 1

Op Amp Builder - Level 2

How can you create an intermediate SPICE model that includes slew-rate limiting and voltage/current output limits? Here's a JavaScript Calculator that shows you how! Add 2nd/3rd poles to capture the overshoot / ringing of a real op amp. Modify it any way you like, create your own models! Learn how JavaScript can create forms, SPICE models and print it to a text box.

Download a simple html/javascript page oplevel2.zip to modify/create your own model.

Explore the basic OpAmpBuilder - Level 1.
Check out other JavaScript Calculators.

To learn to create these SPICE op amp models:
Quick intro and Basic model.
Learn various op amp modelling techniques.

SPICE Circuit

spice model

Enter Basic Behaviors

Aol		Open-Loop Gain (V/V)
fu		Unity-gain Frequency (Hz) or Gain Bandwidth Product (GBP)
Slew Max		Max Vo change per micro second (V/us)
Rin		Input R
Rout		Output R

Enter 2nd and 3rd Poles

fp2		2nd pole
fp3		3rd pole
	Initially set fp2=fp3=10 x fu. Set to 100 x fu to remove effect.

Enter Voltage and Current Limits

Vo lim		How close Vo swings to supply rails
Io lim		Max output current

Enter Model Parameters

Subckt Name		Name for SPICE subcircuit.
Device Name		Name for SPICE subcircuit.
Precision (digits)		Precision for moldel values.

Calculations

C1 = I1max / (slew * 1000000)		Capacitor for slew max and fp1.
fp1 = fu / Aol		First pole filter to acheive fu.
R1 = 1 / (2 * pi * fp1 * C1)		Resistor for fp1 and Aol.
KG1 = Aol / R1		Open-Loop Gain Aol = KG1 R1.*
C2 = 1 / (2 * pi * fp2 * R2)		C for fp2.
C3 = 1 / (2 * pi * fp3 * R3)		C for fp3.
EVL (See code)		Voltage source for Vo Limit.
ECL (See code)		Voltage source for Io Limit.

To copy into text file, First Ctrl-A and Ctrl-C inside box above, then Ctrl-V into text file

eCircuit Center Op Amp SPICE Macromodel