2.1 Add Symbols and Wires

Step One: Place First Three Symbols

For this schematic, the Commonly Used Parts category in the Part Selector contains all the parts except the diode and the MOSFET; therefore, you will place the diode from the model library and then use a built-in keyboard shortcut to add the MOSFET.

In this step, you will place the first three symbols, an inductor, a diode, and a MOSFET. Use the illustration below as a general guide to place the symbols on the schematic.

Inductor: To place the inductor (L1), follow these steps:

1. From the Commonly Used Parts list, double click Multi-Level Lossy Inductor (Version 8.0+).
   Result: The inductor appears on the screen.
2. Move the mouse to where you want to place the symbol, and press the left mouse button.
   Result: An inductor, with reference designator L1, is now in place.

Diode: To place the diode (D1) from the model library, follow these steps:

1. In the Part Selector, double-click the Discretes category to expand the list.
2. Double-click the Diodes category, and then double-click Select from Model Library...
   Result: The Select Device dialog opens.
   
3. In the Filter field at the bottom left side of the Select Device window, put your cursor in front of the asterisk (*), and then type D1n41.
   Result: D1n4148 appears as the only item available.
4. Select D1n4148 in the top right pane, and then click the Place button at the bottom of the Select Device window as shown below.
   Result: The Extract Diode Parameters dialog opens.
   
5. Click Extract to accept the default values and close the dialog box.
   Result: Several SIMetrix SPICE simulations are run on the SPICE diode model and curve-fitting algorithms calculate a set of PWL parameters for use in SIMPLIS simulations.
   Note: Although a small-signal diode such as the D1n4148 is not appropriate for a synchronous rectifier application, you will change this diode model later in section 2.2 Edit Standard Component Values.
6. Place the cross hair  to the left and down from the inductor, and then press the left mouse button.
   Result: A diode, with reference designator D1, is now in place.
7. With the diode selected, press F5 two times to rotate the diode 180 degrees.

MOSFET: To place the MOSFET (Q1) using a keyboard shortcut, follow these steps:

1. Move the mouse cursor directly above the diode, and type M.
   Note: The letter M is a keyboard shortcut which places a 3-terminal N-type MOSFET, as if you have navigated to the Select Device dialog as in Step 4.
   Result: The Extract MOSFET Parameters dialog opens.
2. Click Extract to accept the default values and close the dialog box.
   Result: As with the diode placed in the previous step, several SIMetrix SPICE simulations are run on the MOSFET model and curve-fitting algorithms calculate a set of PWL parameters for use in SIMPLIS simulations.
   Note: The original SPICE model is NOT used in the SIMPLIS simulations. As with the diode, you will change the part number for the MOSFET in section 2.2 Edit Standard Component Values.
3. With the cross hair directly above the diode, click the left mouse button to position the MOSFET symbol on the schematic.
   Result: A MOSFET with reference designator Q1 is now in place.

Step Two: Place Remaining Symbols

To place the remaining symbols, follow these steps:

1. Place the symbols in the order listed in Table 1 below, using either of the following methods:
   • From the Part Selector Commonly Used Parts category, double click the part name.

     or

     Type the keyboard shortcut if one is listed in the table.

2. Each time you place a symbol, move the mouse to the general location as indicated on the diagram below, and then press the left mouse button to place the symbol on the grid.

   Label	Commonly Used Parts	Shortcut	Comments
   C1	Multilevel Capacitor (Level 0-3 w/Quantity) (Version 8+)		No keyboard shortcut
   R1	Resistor (Z Shaped)	4
   V1	Power Supply	v
   V2	Waveform Generator (Pulse, Ramp...)	w	.
   R2	Resistor (Z Shaped)	4	To rotate 270 degrees, press F5 three times.
   	Ground	g
   Probe1-NODE	Probe-Voltage	b
   Probe2-NODE	Probe-Voltage	b
   IPROBE1	Probe -Inline Current		No keyboard shortcut

   Note: If you accidentally place an extra symbol, you can immediately remove it by typing Ctrl+Z or by selecting Edit > Undo from the menu bar. If you did not remove the extra symbol immediately after placing it, see 2.1.3 Remove Extra Symbols and Wires.

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Special Case: Wires Inside a Symbol Boundary

In some cases, you may want to remove wires that are inside the symbol bounds. The following example uses a comparator with the input pins shorted together as shown below. This procedure removes the wires, but leaves the symbol intact.

To remove only the wire segments, follow these steps:

1. Press and hold the Shift key, click and hold the left mouse button as you drag to select the wire area as shown below.
2. When you have defined the area, release the mouse button.
   Result: The wires inside the box change to blue, indicating these wires are selected.
   
3. Press Delete.
   Result: The selected wires are deleted from the schematic.
   

Special Case: Wires Which are Exactly One Grid Square Long

There are times when your schematic will have wires which are exactly one grid square long, and you would like to delete these wires. This is difficult because the program enters the wiring mode whenever the mouse cursor is within one-half grid square distance from a wire end. Here are a few solutions to this problem:

Disable the auto wiring by pressing and holding the Ctrl key when selecting the wire.

1. Disable the auto wiring by pressing and holding the Ctrl key when selecting the wire.

   or

2. Select the wire by dragging a box which encloses the wire.

Once the wires are selected, you can press the Delete key to remove them from the schematic.