MIL PRF 31032 and Updated IPC Performance for Printed Circuits
Multiple standards organizations specify requirements for printed circuit designs, but none are more stringent than IPC and military standards. These standards are important for ensuring a new circuit board will be reliable in harsh environments. These two sets of standards can be confusing, it’s impossible to check your layout against every standard quickly. The rules-driven design environment in Altium Designer solves this problem by allowing you to set IPC and MIL standards in your design rules.
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Find the right software that can get your circuit board up to compliance standards.
Originally issued during the mid-1970s, MIL-STD-275 covered requirements for printed circuit board wiring. The standard underscored the quality of the conductors, the width between traces, trace thickness, and routing. After several updates during the 1980s and 1990s, the Department of Defense cancelled the standard in 1994. Since then, the standard has been replaced with IPC (Association Connecting Electronics Industries) standards. In addition, the US military adopted MIL PRF 31032 to supersede the MIL-55110 standard for printed circuit boards.
As MIL-STD-275E no longer exists as a regulatory framework, the Department of Defense relies on military printed circuit designers to obey two IPC standards and the MIL PRF 31032 standards that define PCB design and fabrication requirements. PCB designers and fabricators must comply with the IPC-2221 “Generic Standard on Printed Board Design“ or the IPC–D–275, “Design Standard for Rigid Printed Boards and Rigid Board Assemblies.” The IPC-2221 and IPC–D–275 standards provide a broad framework for designing and producing printed circuit boards that can withstand harsh environmental conditions demanded by the military.
Because these standards relate back to important design choices, printed circuit design teams need tools to help them make sure they obey these important standards. The schematic design and PCB layout features in Altium Designer are built to handle all aspects of circuit board design to ensure you can comply with military specifications. Keep reading to learn more about important military standards you need to encode as design rules in your PCB design software.
The IPC standards specify electrical, mechanical, and thermal requirements for printed circuit boards that companies want to sell on the market. Note that IPC standards are not required for consumer products, but many companies know they are intended to ensure reliability. Therefore, they may not accept products that are not designed to IPC standards. IPC-2221 and IPC-D-275 have superseded the older MIL STD 275 standard for printed wiring boards.
In contrast, the military does specify that certain IPC and MIL standards must be followed in order to do business with the government. Every PCB purchased for the Department of Defense must meet the MIL PRF 31032 standard, and fabricators must work through extensive auditing programs to verify that processes and products comply with the standards. The MIL-55110 Qualified Products product assurance program has been superseded by MIL PRF 31032, and designers must create PCBs for military systems to these new standards.
What’s Affected by IPC and MIL Standards
Your Schematic editor and PCB editor utilities need to consider all aspects of the IPC and MIL standards for a printed wiring board. In your schematic diagram, you’ll need to make sure your circuit board components have IPC-compliant land patterns, annular rings, pad and trace spacing, and other aspects that are controlled during routing. MIL standards place requirements on PCB stack-up thickness, minimum hole size and aspect ratio, minimum trace width and spacing, component tolerances, and conductive finishes.
Other issues covered by the IPC standards include environmental conditions, component/circuit density, coatings, component placement, mounting holes, the placement of brackets and hardware, conductor routing, conductor width, board shape and size, and connector contacts. In addition, the standards cover ESD sensitivity, board flexibility, substrate materials, signal integrity, the number of signal layers, design reuse and other factors.
- Aerospace and naval applications often require systems that can withstand high pressure and high temperature.
- Your components and footprints should be designed to IPC standards on pad and hole sizes.
- The mil-aero market has a variety of design standards that are not encoded in IPC or MIL standards.
Altium Designer’s hole, pad, via, and trace clearance rules help you stay compliant with IPC-2221 and MIL PRF 31032.
Everything from hole sizes to trace width and clearances are defined in IPC and MIL PRF 31032 standards. How can you ensure your designs will meet these important standards? This is where the design rules tools in your PCB design software are used to establish instructions and constraints for the PCB Editor. Because the design rules define routing widths, clearances, routing through styles, and plane connections, the correct application of the design rules also establish the appropriate component-to-component and component to board clearances.
Achieve the Correct Component/Circuit Clearances with Altium Designer
Defining the width and clearance for routing establishes fabricator requirements and IPC standard compliance. With the routing width and clearance established, design teams can use Altium’s PCB Editor to define the PCB area available for component placement and routing. The PCB Editor maximizes the free space between components by placing similar-sized surface mount components opposite one another on double-sided boards and by placing components on pads established to a regular grid.
In complex designs, such as rigid-flex PCBs or multi-board assemblies, a designer might make an error during layout and routing. Defining constraints through Altium Designer’s Design Rule Check (DRC) engine establishes specific electrical design rules for PCB components, schematic diagram, and PCB layout. The online DRC engine in Altium Designer spots any errors that might violate IPC and MIL PRF 31032 standards. Make sure to define these standards as design rules before you start creating your next military PCB.
- Pad and trace clearance requirements are defined to ensure your board will not exhibit unintended ESD and component failure.
- Military systems might need to operate at high temperature, which will put limits on the maximum current that can be used in these systems.
- The right PCB design software package can help you quickly generate documentation directly from your design data. This helps you stay compliant and properly communicates your design intent.
Take a software that has its own IPC compliance wizard
Within Altium Designer, you’ll have a set of design tools to help you stay compliant with military and IPC standards. The CAD features are customizable and interface with a rules-driven design engine, which instantly checks your PCB layout against your design rules as you create your circuit board. Altium’s interactive routing provides the precision needed for an IPC-compliant PCB layout. Using the Routing Width Design rule and Track Width Mode setting within interactive routing eliminates the possibility of routing conflicts, collisions, and errors. Both tools establish constraints for the trace widths.
Components used in military systems must also be procured from ITAR-compliant and registered suppliers. To aid in this area, Altium Designer’s Active BOM tool functions as a Bill of Materials editor and offers real-time component, availability, costs, and supplier information. Your component data and your PCB layout data then get imported directly into your manufacturing documentation, giving you everything you need to produce and assemble your board to military specifications.
Altium Designer Supports MIL PRF 31032 and IPC Standards Compliance
Because Altium Designer functions within a unified design environment, design teams can rely on a full suite fo design tools that comply with IPC and MIL PRF 31032 standards. The unified environment found within Altium Designer combines design rule checks, electrical rule checks, and simulations to ensure your circuit board functions as designed. You can design a schematic, create a compliant PCB layout, and prepare your circuit board for manufacturing with Altium Designer.
- Whether you’re designing to civilian or military specifications, Altium Designer provides everything you need for circuit board design and fabrication in a single application.
- An integrated rules-driven design engine checks your schematic and layout as you create your design. This helps you stay compliant with IPC and MIL PRF 31032 standards.
- The 3D ECAD/MCAD tools in Altium Designer give you a complete set of features for product design. You can check your board inside your enclosure before sending your designs out for manufacturing.
Enforce military specifications in your schematic and PCB layout with the 2D and 3D printed circuit design tools in Altium Designer.
Military PCBs carry strict requirements on schematic design, circuit board layout, and components. With the layout and sourcing features in Altium Designer, you can ensure your board complies with the MIL PRF 31032 standard and IPC standards for electronic products. The rules-driven design engine lets you define these important standards as design rules so that your new circuit board will be reliable and compliant with military specifications.