In this section, let’s learn some basic knowledge about Schematic Basics ADS.

First, we need to select the appropriate Palette from the Library Palettes on the left side of the Schematic window to select components or perform appropriate simulations.

Among them, “Setuo Favorite Palettes…” can mark the commonly used Palettes, which is convenient for quick selection in subsequent designs (no need to flip up and down).

Another thing to note is the toolbar above the window , which already provides some commonly used shortcuts. By right-clicking the mouse in this area, you can add your favorite functions or hide functions that you don’t need.

Among them, the “search” function is more useful. You can directly search for specific components or search across designs.

Now, let’s create a simple Schematic and select “Lumped-Components” (Lumped components refer to those electronic components that can be regarded as concentrated at one point, which is opposite to distributed components. Lumped components mainly include resistors, inductors, capacitors, transformers , etc. Their electrical characteristics can be described by simple lumped parameters (such as resistance value, inductance value, capacitance value, etc.)). Let’s place three inductors first. After placing them, you can right-click to exit the current selection (the shortcut key is ESC, press F to adaptively display the size and position, hold down the right mouse button to move the view, and the mouse wheel can zoom).

Then we place two capacitors. You can see that the default direction of the component is horizontal, so you can click in the toolbar or use the shortcut key “Ctrl+R” to rotate it (before placement).

Then, we use the (insert Wire) in the toolbar or the shortcut key “Ctrl+W” to connect the ports of the components. Then, if the circuit needs to be grounded, you can use the quick insert GND in the toolbar. GND can be directly connected to the port of the component or at a certain distance from the port and then connected with Wire. Moreover, many times we will do some secondary designs, and at this time we need to connect some pin ports. You can use the pin connection in the toolbar to ensure the correct number of pin ports. And click or use the shortcut key “Ctrl+S” to save the design.

If we want to use the current design as a sub-design in subsequent circuits, we can create a new Symbol under the Cell where the Schematic is located to facilitate subsequent quick calls.

When creating a Symbol, you need to first select the corresponding design, which is Design1 in this case.

Then click “Create Symbol” and a Symbol design selection window will pop up:

Some of the settings are explained below:

• Auto-Generate / Copy/Modify: The former automatically generates a Symbol based on default settings, and the latter allows you to copy an existing Symbol and modify it.
• Source view: Select the source view generated by the Symbol (for example, schematic).
• Symbol Type: Dual (a symbol with two ends), Quad (a symbol with four ends), Look-alike (similar to an existing symbol), Create one Symbol Pin per EM Port (a Symbol pin is created for each EM port) .
• Order Pins by: Select how the pins are ordered around the Symbol.
• Symbol Size: Lead Length (default is 0.25, the unit is determined by the previously selected Library), Distance Between Pins (default is 0.25).
• Shape: Select the shape of the pin (eg dot).
• Symbol Pin Label: Pin Name (pin name, for labeling), Pin Name :: Net Name (labeling with pin name and net name).

This time we will not modify it, all take the default value, press “OK”:

You can see that the pins in the generated Symbol correspond to the pins added in the sub-design. If you want to use this Symbol in other designs, just click and hold the left mouse button and drag it into the new design.

At this point, select the Symbol and click in the toolbar to view the specific design of the Symbol. Similarly, click to return to the previous level design.

Double-click a component to see all the parameters that can be modified for the component. Taking the inductor as an example, the adjustable parameters include L (inductance value, in nH), R (resistance, if left blank, no resistance is assumed ), Temp (temperature, used to specify the operating temperature of the component), Trise (rise time, indicating the component response rise time), Tnom (nominal temperature, usually used for temperature-dependent parameter calculations), TC1 (first temperature coefficient , used to describe the linear relationship between inductance value and temperature change), TC2 (second temperature coefficient, used to describe the quadratic relationship between inductance value and temperature change), InitCond (initial condition, usually used for the initial current or voltage value in transient analysis), Noise (noise, specifies whether to consider the noise characteristics of the component, the default setting is yes), Model (specifies the model name of the inductor), and _M= (model coefficient, used for specific configuration of the model, usually related to advanced models).

You can also modify the parameters by clicking the left button of the mouse on the corresponding position of the parameter in the Schematic View and changing the parameters to the values ​​​​in the figure (all of them are empirical values, set arbitrarily, and will be adjusted later according to the simulation results):

Then you can return to the main design.

Next article: ADS Tutorial (Part 3) S-Parameter Simulation