Analog Filter Synthesis and Design: Cadence circuit simulator

Try these handouts in the following order. By now you must have physical access to 1218 Mudd and accounts on computers there. CAD Tools Information page from CISL has general information on using this lab. In case of any problems with access or use, send an e-mail to nkrishnapura@mltc.com.

Useful links on CAD and its usage in 1218 Mudd can be found at the bottom of Prof. Ken Shepard's homepage for E4321.

• Simulating circuits using spectre. You'll be simulating the circuits that I have already set up.
• Schematic entry tutorial. Follow the steps here to follow Cadence's tutorial on entering schematics. Try it out throroughly to get comfortable with entering schematics-You'll be using it extensively. Use ~/courses/E4215 as your working directory so that the default setup works conveniently.
• A very brief introduction to the Waveform Calculator.

• Parameterized subcircuits: I have created a parameterized first order filter lpf in the library E4215_examples. Study the schematic and understand it. The parameter wp sets the cutoff frequency in radians per second and the parameter gain sets the dc gain. The cell lpf_example uses this subcircuit with different parameters to create two low pass filters with different gains and bandwidths. Selecting an instance of lpf and hitting q displays the parameter(s) and their values for that instance.

  Study the two schematics lpf and lpf_example and understand them. Simulate these circuits and verify that they work as expected. You can also copy these circuits into your library, change the parameters and see the effect. In the subcircuit, you will see that some components have variable values labeled pPar("variable_name"). This enables them to be set for each instance of the subcircuit.

  You can consult the Schematic entry tutorial to learn how to create symbols for subcircuits.

You will be using parameterized subcircuits in HW8.

With the above, you should be able to make your own circuits and simulate them. You can try out circuits from old homeworks.