Build a schematic and Simulate it with Spectre

Authors: Jihoon Jeong, Shaver Deyerle, Justin Cartwright, Dr. Dong S. Ha

We will have a Virtuoso Schematic Editing Window if you have followed every step correctly. In this section, you will learn how to build a RLC network in Cadence. Let's build a simple L-match transform network which is supposed to transfer the maximum power at a resonant frequency of 500 MHz from source resistance of 50 Ω to load resistance of 500 Ω. Hope you can calculate Q and L, C values before you use given values for L, C later.

1. With Schematic Editing Window activated, hit 'i' key or click on Add->Instance on the top menu. Another way to add instances is to click the chip picture on the left toolbar. (Fig. 6)

Figure 6. Add instances on Schematic Editing window dialog-box

2. An Add Instance window will appear. Click a "Browse" button, a Library Browser window will pop up. Select analogLib* library from top-down lists, add an inductor(ind), and a capacitor(cap) from Passives category by clicking instances in Component Browser window and placing your curser on the Schematic Editing window. (Fig.7) Make sure that you clicked "View Name" of symbol for instances. Now, we're going to use 2-Port Analysis in which each port represents source or load port. We will be able to add a resistance value when I add a port component.

Note: In this tutorial, we will use ideal passive components from analogLib* library for an educational purpose, however, in the future we will design a circuit in tsmc18rf technology.

Figure 7. Select instances from Component Browser

3. While placing instances on the Schematic Editing, replace a value of "Inductance" to 'L' shown in Fig. 8. Repeat the same procedure for the capacitor('C') respectively. Hit 'ESC' to escape from any previous action.

Note: If you want to change a property of a component at any time, click the component and hit 'q'. Edit Object Property window will show up and you will be able to modify any value of the object.

Figure 8. Change a property of an instance

4. To analyze a parallel RLC network, add ports and a ground into your schematic. The port can be found in analogLib->Sources->Ports->Port. (If you can't see "Sources", please make sure you have checked "Category View" in the Library Manager) The ground component is available in analogLib->Sources->Globals->gnd. When placing these port sources, you will notice that a default name will be either 'port0' or 'port1'. You should rename the first port to 'P1'. The Resistance should be 50 Ω (or make a parameter, Rs). Place the port, P1, vertically to the left of the RLC network. Create another port called 'P2' with Resistance of 500 Ω (or make a parameter, Rl) as we intended. Place the second port vertically to the right of the RLC network.

Figure 9. Place ports and gnd

5. In order to connect those components in your schematic, hit 'w' and wire those. Alternative ways to initiate wiring are Add->Wire from the top menu and click the wire picture from the left toolbar.

Note: Please refer to the Fig. 10 to properly wire L and C with 2 ports.

6. Check and Save the schematic by hitting Check and Save button. You must click on this button before you run any simulation, or your simulations will not take place. Look in the CIW window and verify no error. (Fig. 10)

Figure 10. Wiring and Check/Save

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