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Full Custom IC Desig..

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Now go ahead and simulate your circuit as you did previously in Part 3 of the tutorial. From the<br />

schematic window, go to Tools SAE to open a new SAE window. When comparing the two<br />

waveforms (inverter parasitics to inverter without parasitics) take note of the difference between<br />

delays from VIN to VOUT for transient waveforms.<br />

Part 7: Hierarchical <strong>Desig</strong>n<br />

Using smaller instances of circuits to create a larger design is what hierarchical design is all<br />

about. In this section, we use an inverter we created earlier and use several instances of it to<br />

create a five stage oscillator in schematic and layout views.<br />

Create a new schematic for the ring oscillator by going to New CellView from the <strong>Custom</strong><br />

<strong>Desig</strong>ner Console and setup the options as shown in figure 81 below. The setup is as follows:<br />

Library: mylibrary<br />

Cell Name: ringOscillator<br />

View Name: schematic<br />

Editor: SE - schematic<br />

Click OK when done.<br />

San Francisco State University Nano‐electronics and Computing Research Lab 75

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