So, you need to add more complicated structures into your package design. What options do you have available to you in the Cadence packaging products with the 17.4 release – whether you’re using the base Allegro® Package Designer Plus or have additional options available?

The answer to that is, quite a few! In even the baseline product, you can import structures from external tools via an RF Symbol Wizard. The Coil Designer available with the Allegro® Productivity Toolbox option offers you many configuration options for dynamic generation. And, if you have the SiP Layout option (all of you who have moved up from the 17.2 SiP Layout tool already have this!), the L-Comp Structure generator is there for your usage, too.

Allow me just a few minutes of time, and I’ll walk you through the different options. From there, if you have questions/concerns, or just want help to decide which tool makes the most sense for your flow, your customer support team is right here to help you make those tough calls.

RF Symbol Wizard 

First up, the RF Symbol wizard. This feature is available to everyone in the base product line. To find it, from the File – New menu, pick the Package Symbol (Wizard) entry and give your future symbol a design name.

From there, you will be shown a list of available symbol types. Right there at the bottom of the list, you will find the RF Symbol option. This is currently a prototype command as we work with all of you to gather feedback on the current command and what options are missing.

To create the symbol, you will need the source GDSII file and a layer conversion file (you can define the layer mapping during the wizard if you don’t have one). In addition, you’ll need to know what padstack to use for the pins of the symbol. That’s it! At the completion of the wizard, you can automatically generate your compiled PSM symbol database if you want; no other input from you is needed.

The symbol you are left with will look something like the following simple example. Of course, yours will probably be significantly different. The shape and characteristics will depend heavily on its application.

Today, the wizard allows you to import from GDSII (stream) data, but maybe your RF designer exports to a different data format. Do they give you an entire library of RF elements at one time and a batch flow to import all of these would be more efficient than a single symbol at a time? Let us know so that we can make this the most powerful wizard around!

Coil Designer

Okay. You don’t have a GDSII file from your RF engineer. Maybe you don’t even HAVE an RF engineer, or you are just prototyping things based on some simple parameters. Can you still make a coil? If you have the Allegro Productivity Toolbox option, that’s an emphatic “YES!” With the option checked out, you’ll find the Coil Designer under the Route menu. Running it will present you with the following:

You can choose from various coil styles and modify the parameters. As you do this, the resulting coil is constantly being updated on your cursor. The real-time feedback this offers is (to me) invaluable. I don’t have to guess what my coil parameters translate to. I can position the cursor over the space that I must place the coil in and immediately see if it will fit within the bounding box constraints.

Other than that, you’ll see further options for optional route keep-outs above/below to make sure that nothing interferes with the coil. You can choose from a cline-based or shape-based coil, too. I would recommend cline-based if possible, as this is easier to extract data such as line width, length of the path, etc., than using a shape representation will.  

L-Comp Structures 

If you are a long-time SiP Layout customer, or you have purchased the SiP Layout option on top of APD Plus, then you have access to advanced structures. These extend the basic via structure scheme to include high-speed structures built by/with your SI engineer as known-good structures. Or, you can define L-Comp (inductive compensation) structures.

There is a wealth of options here. Covering them all in this post would be difficult. But, like the other structure types, the creation tool itself provides a detailed description of the parameters and a how-to flow for properly defining your symbol.

I think everything is laid out very well in the description, allowing you to walk through and define your structure in a few quick clicks. When you click on the Generate button (bottom right, above the Reset and Close buttons above), the structure will appear on your cursor, like the Coil Designer, so that you can determine whether it will meet your placement requirements or needs further adjustments.

How Do You Use Structures?

Have you used any of these commands in the past to improve the SI characteristics of your layout? What were your results? Could they be made to work better for you, or is there a type of structure you need to be able to create that isn’t easy with any of the available commands? If so, we’d appreciate hearing from you so that, in upcoming releases, we can offer you everything you need to develop and manufacture any IC package design you can imagine!