All of today’s “smart” devices—including computers, phones, appliances, tools, vehicles and other electronic systems—are controlled by a central processing unit (CPU). Understanding CPU architecture and component usage are essential for designing and building the PCBAs that drive the array of products that have become such important elements in our lives.
What Exactly Is a CPU?
In electronics, terms can sometimes be shrouded in ambiguity. This is certainly true when describing processing units; therefore, a few definitions will help explain just what a central processing unit (CPU) is and its role in most applications.
Processor is the generic term for an electronic component or device that controls or drives the functionality of a larger electronic circuit or system.
A microprocessor is an electronic device, typically an IC, that includes processing elements such as an arithmetic logic unit (ALU), a stack, memory and a control or processing unit.
Central Processing Unit (CPU)
The term central processing unit is used interchangeably with both processor and MPU to indicate the unit, component or device that performs the processing activities for an electronic system.
As these definitions indicate, CPU can be an ambiguous designation. However, CPU is often the preferred term for the control device used within a computer while the term, processor, can refer to a device for specific functionality control in other types of electronics systems.
CPU Usage and Applications
The most familiar way to describe the CPU is as the brain of the system where it is installed. A more technical explanation describes the CPU as the component or device that interprets data and information, initiates actions and executes instructions. To accomplish these tasks, the CPU consists of a number of internal elements—and there are several types of CPUs.
Types of CPUs
Although internal elements and connectivity may vary to a degree for different CPUs, the CPU architecture or type is categorized by its core. The core is the smallest processing unit that is capable of performing all of the CPU’s essential functions. There are several common architectures in use today, including the following:
Many computers are equipped with multi-core processors that are tasked with performing specific actions. For example, one core may only perform mathematical calculations. When designing boards that contain CPUs, the core is a primary factor that affects the PCB layout.
Manufacturing Considerations for Different CPU Architectures
For boards that contain CPUs, such as motherboards, several factors must be considered to accommodate the CPU architecture while adhering to the manufacturing constraints defined by your CM’s DFM and DFA guidelines.
Essentials for Designing CPU Boards for Manufacturing
- Apply good grounding design techniques.
CPU boards typically contain multiple signal types, which necessitate signal integrity design best practices, such as component type isolation. And for multisignal boards, good grounding should be utilized to minimize interference.
- Perform thermal simulations.
CPUs are invariably high-temperature devices. Therefore, it is important to consider thermal dissipation and distribution during design. By performing thermal simulation and analysis during design, manufacturers can ensure that heat is adequately distributed and removed from the board.
- Consider board depanelization requirements.
Due to the number of external connections necessary for CPU boards, manufacturers can consider depanelization during design to ensure board clearance rules are not violated.
|Tempo's Custom PCB Manufacturing Service
All board designs should follow a checklist for manufacturing optimization to ensure your built boards will be structurally sound and meet operational lifetime requirements. However, for CPU boards, special attention should be paid to the essentials listed above.
Tempo Automation leads the industry in building complex PCBAs—like CPU boards—fast and to the highest quality for prototyping and low-volume production. We will work with you to ensure that your boards reflect your design intent and also satisfy all manufacturing constraints.
And to help you get started on the best path, we furnish information for your DFM checks and enable you to easily view and download DRC files. If you’re an Altium Designer or Cadence Allegro user, you can simply add these files to your PCB design software. For Mentor Pads or other design packages, we furnish DRC information in other CAD formats and Excel.
If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on how the CPU architecture can impact the building of your PCBAs, contact us.