Applying IPC Standards to PCB Layout Design

Key Takeaways

• Learn why it’s important to comply with IPC standards for PCB layout design.

• Find out which IPC standards are relevant to PCB layout design. 

• Learn how the choice of PCB software affects IPC standard implementation.

As I approach my forties, my definition of success is very different than it was in my twenties. To me, success is no longer about having millions of dollars in the bank or flaunting fancy sports cars. Instead, it’s about the ability to raise my child to be a kind person with good decision-making skills. 

If there’s anything that I’ve learned after spending over 3 decades on earth, it’s that, in most cases, there isn’t a standard definition for success. However, there are some exceptions to this—if you’re hoping to produce a functional and reliable PCB, there are definitely firm standards of success. Abiding with IPC standards for PCB layout designs can help you achieve a successful design. 

Why Is It Important to Comply With IPC Standards for PCB Layout Design? 

PCB designs that are compliant with IPC standards are generally more reliable

It’s tedious to read through pages of IPC standards, however, they are there for good reasons, particularly for PCB layout designs. The IPC was established in 1957 and at the time was known as the Institute of Printed Circuit. Today, thousands of companies that are part of the PCB design supply chain are members. 

IPC produces and maintains standards that serve as a common guideline for PCB design, fabrication, assembly, test, and other areas of concern. For PCB designers, complying with the relevant IPC standards for PCB layouts can make a difference in a product’s success or failure.

There are just too many variables in PCB design that can affect the reliability and manufacturability of a board. For example, designers could turn to guesswork for the perfect pad size for through-hole components. Designing without the guidance of IPC standards might also lead to non-conformance of uniformity between designers and manufacturers. 

Which IPC Standard Should You Use for PCB Design Layouts?

PCB design layout with the IPC-2221 Standard

IPC-2221

Throughout the years, the IPC has established various standards that ensure design reliability and manufacturability. For PCB designers, the must-read IPC standard is the IPC-2221. The IPC-2221 is the generic standard that covers almost every aspect of PCB design. 

The standard details how electrical considerations such as PDN bus layouts, conductor clearance, and impedance control should be implemented on a PCB. You’ll also find pages in the standard that focus on thermal design considerations for the PCB. The standard explores various methods of dissipating heat in PCBs and explains how to implement them in actual designs.

PCB design and manufacturing are inseparable sides of the same coin. Some sections of the IPC-2221 helps designers ensure the PCB is optimized for PCB manufacturing. For example, section 9 touches on holes and interconnections, which contain guidance on drill size, land pattern, and conductor spacing on a PCB. 

IPC-2223

The IPC-2221, however, does not cover guidelines related to flex PCB design. If you’re working on one, you’ll need to refer to the IPC-2223, which exclusively focuses on flex PCB structure design. It covers important design considerations such as pad/via placement, bend radius, coverlays, and structural specifications for flex PCBs. 

IPC-2222

Meanwhile, the IPC-2222 is a standard that dives deeper into the requirements for a rigid organic printed board design. This standard goes into detail on factors that enhance the manufacturability of a rigid PCB, including material selection, hole size, interconnects, and mechanical properties. 

Choosing the Right PCB Software Impacts IPC Standard Implementation

IPC Standard implementation with the DRC wizard

Reading the IPC standards isn’t enough to produce PCBs that are both reliable and manufacturable. To do that, you’ll need to implement the standards on PCB software. If you’re using software with limited functionality, you’ll find it difficult to set the required constraints on the software.

For example, the IPC-2221 specifies the recommended component clearance for automatic placement machines. You’ll want to set this value in the software and have it automatically detect violations when the rule is breached.

Component arrangement, thermal management, and other guidelines set by IPC standards are better managed with an advanced PCB design tool. OrCAD, for instance, offers downloadable component footprints that are compliant with the IPC standards for PCB layout design.

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.