Build an Op Amp SPICE Model from Its Datasheet – Part 3
Friday, December 31st, 2010Summary:
In Part 2, we left off at the open-loop bode plot. We saw that it resembles the datasheet. However, our op amp example, ADA4004 from Analog Devices, shows an extra pole after 1 MHz. Indeed, the phase starts dropping after 1 MHz and becomes 45 degrees at 17 MHz. Therefore, we need another pole in our model at 17 MHz.
Build an Op Amp SPICE Model from Its Datasheet – Part 2
Sunday, November 14th, 2010Summary:
Part 1 of this article shows how to create a behavioral model of an operational amplifier based on the following parameters found in the datasheet: Input and output resistance, input capacitance, DC gain, and offset voltage. As an example I chose Analog Devices’ ADA4004. Let’s continue building this model to simulate the Gain Bandwidth Product.
Build an Op Amp SPICE Model from Its Datasheet – Part 1
Monday, October 11th, 2010Summary:
Why do you need to build your own Op Amp model? Most Op Amp manufacturers have SPICE models for their components and make them available for free. Then why should you know how to build one? Well, not everything has a model and that is why, sometimes, you have to build your own. Also, it may be necessary to study a circuit to see what happens if you change the Op Amp slew rate or bandwidth, offset, and so on. Sometimes the manufacturer own model does not work, as a user found out and posted a question in this forum. I told him that the model does not work and advised him to build his own. …
An Ideal Operational Amplifier Simulation Model
Saturday, August 28th, 2010Summary:
You worked hard on your schematic, you calculated everything, you feel confident that it will work. To be sure though, before committing the schematic to copper, you want to simulate it. You develop a SPICE simulation schematic and, surprise, things don’t work. What’s going on?
