Most medium- to large-size companies have a hierarchical organizational structure, where emphasis is placed on top-down reporting relationships. A typical organizational chart outlines reporting relationships between employees and their supervisors, as well as functional interaction between employees. By knowing who reports to whom, it is easier know who to go to for specific questions or tasks.

Similarly, as ECAD designs become more complex, spanning several schematic sheets, they can quickly become difficult to manage, especially when there are multiple designers working on the same design.

What is a Hierarchical Schematic Design?

Hierarchical schematic design, sometimes referred to as modular or block design, is where different schematic designs are represented by block symbols on the top sheet of the main design. Larger designs may also have more than just one top sheet with block symbols. In some cases, a block symbol on the top sheet will represent another sheet with additional blocks symbols on it.

Each block symbol on the top sheet represents its own schematic design. A processor design with a power supply and CPU is a good example. The power supply and CPU can have their own block symbols on the top sheet of the processor design. See the example in Figure 1 below.

Figure 1: Processor design using block symbols

How a Hierarchical Schematic Layout Can Help You

A hierarchical schematic enables designers to see system level functions of the design from the top sheet and then descend down into those functional areas through the individual block symbols. This is an invaluable organizational tool for the schematic view that will help engineering, test and field technicians. Additionally, a hierarchical schematic design process provides the following benefits:

• Hierarchy reduces the workload for identical blocks of circuitry. For example, if designing an eight-channel circuit, the designer doesn’t need to create eight identical channels of circuitry. With hierarchy, the designer creates one schematic of channel circuitry and places eight block symbols that point to the same channel design.
• Hierarchy facilitates team design. With the ability to easily add block symbols that point to different schematic designs, multiple engineers can work on separate areas of the design in parallel which can reduce the design phase of product development. For example, this enables the concurrent development of the power supply design along with the CPU design. When the design teams are ready, the power supply block symbol and the CPU block symbols are added to the main design.
• Hierarchy enables design reuse. The modular designs, such as the power supply, can be externally so that they are accessible to other designers to reuse in new design concepts that requires them.

3DEXPERIENCE PLM Collaboration Services for Altium Designer (UET) allows designers to leverage the hierarchical schematic design methodology in a secure and flexible environment. Figure 2 below is an ECAD design which has a top sheet and eight different block symbols. PLM Collaboration Services for Altium Designer allows the designer to save any one of the block symbols independently of the other block designs, PCB, and project. So for example, rather than waiting for the other designer to finish their portion of the design, Designer A can work on the USB Controller (USB_CY7C68001-56LFC.SchDoc) schematic and Designer B can work on the Ethernet Interface (Ethernet_RTL8201CL.SchDoc) schematic simultaneously. This decreases product development time and also the time to market, leading to improved productivity and reduced costs.

Figure 2: A Top Sheet which has eight different block symbols

Furthermore, when Designer B has completed designing and testing the Ethernet Interface design, he can make it available to be used by other designers within his company when he saves it to 3DEXPERIENCE (see Figure 3). This makes it faster and cheaper to design and build a new product, since the reused Ethernet Interface design will not only be already designed, but also tested for reliability.

Figure 3: Saving a schematic sheet to 3DEXPERIENCE

Using hierarchical schematic design techniques can help you better organize your design, decrease your workload and involve more team members.