You may find yourself having to redesign some major portions of your circuitry to correct these problems. Many of these settings can be transferred in templates or readme files, which can be very helpful when beginning a new design. At this point, the board is ready for the layout to start. Maneuvering components around on the screen with their net connections rubber-banding between them is one of the best and most challenging puzzles that you can work on.
Although this should technically be caught during design synchronization, designers should still ensure that they are using the correct footprints. Whether a PQFP is being used instead of a BGA, or the polarity of a capacitor is reversed, footprint errors like these will require a redesign if not caught the first time around.
This is especially true of high-density designs where every millimeter of space counts. Designers who fail to do this may have costly redesigns ahead of them to improve the performance of the board. Using the schematic to place logical groups of components or designating placement rooms on the board can be very helpful in preventing partitioning errors. DFM is essential: Ensuring the manufacturability of a circuit board is just as important as signal and power integrity in the design.
These include minimum clearances around components for automated assembly equipment and test equipment, as well as room for technicians to debug and rework the board. Remember to design the PDN: While laying out the board for good signal integrity is essential, it is just as important to focus on the power delivery network PDN as well.
It can be easy for designers to relax their diligence when it comes to laying out power supply components and thereby introducing noise and other interference into the design. Make sure to follow good PDN design guidelines and use the power integrity tools of your CAD system to check for errors. Using the design constraints as shown here can allow you to set up the correct rules for your routing.
Routing traces on a printed circuit board layout is a very rewarding task. As each routed trace is completed, its corresponding net connection guide is eliminated—bringing you one step closer to finishing the job. It is also very easy for design errors to creep in that can undermine what you are trying to accomplish, so designers must stay vigilant. Here are some examples to keep an eye out for. Escape routing: Surface mount devices need traces routed out of their pads into vias for interconnecting on other layers of the board.
This is known as escape routing, or via fanout routing, and is fairly straightforward with most SMT devices. Once selected in the schematic, the corresponding net will immediately be highlighted over in the layout. For those design tools that use a separate utility to manage the design rules and constraints, there is an additional benefit as well. By selecting a net out of the constraint manager, you can see it highlighted in both the schematic and the layout at the same time.
Selecting the group of nets in the schematic, highlights them in the layout and in a 3D view. The more advanced the design tools are that you are working with, the more that you can do with cross-probing. In the picture above you can see that a group of nets were selected in the schematic, which in turn automatically selected the corresponding net objects in the layout.
At that point, we invoked the 3D canvas on the selected objects in layout, and you can see how the routing of these nets is displayed in 3D. This will give you a unique view of how your nets are routed, which can be especially helpful when working with high-speed signal paths. OrCAD has the schematic capture, PCB layout, constraint manager, and 3D canvas tools all configured to work seamlessly together in order to provide you with a complete set of design tools that will get the job done.
Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC industry standard. If thermal management is a problem in your PCB, you can map heat flow and steady state temperature in your Here are a few key things to remember to better understand and properly use the PCB via design rules in your circuit board layout.
PCB post-layout simulation can help designers find and correct signal and power integrity problems in their designs while still in layout. To avoid signal integrity problems in their layouts, design engineers need to be familiar with PCB design guidelines for high speed.
To validate the integrity of PCB assembly, circuit board manufacturers rely on automated circuit board testing systems. Choosing the best-priced components to use on your circuit board can save you a lot of money as long as you look at component cost volume analysis first.
With rising circuit speeds and increased noise and interference, PCB layout designers can no longer afford to ignore PCB impedance control. PCB designers should understand these high-speed analog layout techniques for the best results when designing mixed-signal circuit boards. To ensure layout success, it is essential for circuit designers to fully use their PCB design rules for digital circuits. The best PCB thermal relief guidelines should be used to create dependable connections both electrically and for manufacturability.
Depending on the nature of their application, flexible printed circuits have unique requirements for footprints. Understanding PCB grounding techniques can help a designer lay out a circuit board with better signal and power integrity. For the best board layouts, you should follow a comprehensive set of PCB via size guidelines that adhere to standards and support your other design decisions.
What is Lean Manufacturing? The most important question for lean manufacturing For a lean PCB manufacturing operation, value can be added by making the best use of people, process, and technology.
People, Process, and Technology Although, lean principles can be expressed in terms of various steps , the core tenets are as follows: Getting the most from people: It has been said that a happy employee is more productive.
Streamlining processes: Streamlining or simplifying the process is another important aspect of lean manufacturing. Using the right technology: The competitive nature of the PCB industry requires that your boards are of high-quality and reliable for their operational lifecycles. Essential Design Tools for Lean Manufacturing The decisions that you make during design determine how your board will be made and whether it can be made at all.
The first is incorporating automated generators or wizards like what is pictured above. These allow a designer to specify layer counts and configurations for the stackup while the tools do the heavy lifting of creating it in the database. The next would be to give the designer total control over the layer stackup details including the ability to specify conductive and dielectric board materials.
The designer should be able to specify values and tolerances as well as configure how the layers should be arranged when they set up the parameters of the layout. However, not all of the help that a designer needs can come from the tools. There is a lot of industry knowledge that designers need to be able to better understand the materials and processes that they are working with.
Here is where the designer could benefit immensely by developing relationships with their PCB contract manufacturers in order to get accurate information for creating their board layer stackups.
As has been said, the manufacturers have been doing this job for years and years, and they are very good at it. Layout designers should be encouraged to engage early on with their PCB CMs in order to have the correct layer stackup before they begin their PCB design. Lastly, being able to merge the tools with the industrial knowledge of the contract manufacturers would be the best of both worlds. Allegro provides the capabilities for designers to communicate bi-directionally with participating manufacturers in order to exchange board layer stackup information through the IPC format.
Designers can receive board layer stackup information directly from the CM and then send them fabrication and assembly data for manufacturing.
Allegro is a full-featured design tool that can take your design from schematic all the way through layout. In the picture above, you can see the six-layer board stackup that was generated automatically using the Allegro board creation wizard.
Notice that the values are all generic with a couple of the pull-down menus displayed to show the board dielectric material options that are available for the designer to choose from.
In the picture below, the layer stackup has been fully completed. Additional layers have been added, including silkscreen, solder paste, and solder mask. Also, layer names, functions, and widths have been added, as well as fine-tuning for the board materials and dielectric constants.
Now that these layers have been fully defined, they are properly configured to work with the rest of the functionality in Allegro PCB Designer to calculate controlled impedance routing and other design data. With advanced PCB design tools like Cadence Allegro , you will have the capabilities that you need to fully setup and configure your design for layout.
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