It is beyond debate that the most important elements of a circuit board are the components. After all, a PCBA cannot operate without them. This is why component selection is such a critical aspect of electronic system design. Choosing the right parts is only the first step—it must be coupled with an effective PCB component sourcing process. In this article, we discuss how to define and execute the best component acquisition method for your design objectives.
PCB Component Acquisition Criteria
In many cases, it may be tempting to simply select familiar parts that meet performance objectives that will enable the circuit to function. There are advantages to this strategy; for example, opting for components that have been previously used may limit or eliminate some vetting or testing during your board development. At best, this technique may be sufficient for acquiring common passive and/or active components, but is usually not comprehensive enough for a new, custom design.
The importance of sourcing and procuring components demands that a well-defined criterion be established to optimize board development and support efficient PCBA production. This criterion should include the following objectives:
- Components should meet performance objectives.
All components must meet functionality requirements to ensure a board’s circuit(s) operate as intended. For new components, this can be verified by testing during the prototyping stage.
- PCB design data should be available and well-defined.
In order to create schematics and design PCB layouts, symbol and footprint images and dimensions should be easily accessible. Datasheets are often relied upon for this information, especially when designs must be created from scratch. However, ECAD can be significantly streamlined by using free PCB footprints and symbols from a reliable online source.
- Components should be of good quality.
The quality of the components you use will impact the performance and dependability of your boards once deployed. Therefore, quality should be a priority and is best assured by using reliable distributors for your component sourcing and procuring.
- The supply chain should be secure.
Another important consideration that may impact component quality is supply chain management. Neglecting to ensure a secure supply chain may result in counterfeit electronic components winding up on your PCBAs.
- Supply should be adequate.
After your PCBA has been developed and moves from prototyping to production, one of the most important concerns is an adequate supply of components. Component shortages can delay or halt board production. Therefore, all available steps—such as avoiding obsolete electronic components that will not be available for high-volume production—should be taken during the design process.
The tenets listed above should inform not only your choice of components, but also from where they are sourced and procured.
Options for Sourcing and Procuring Components
When selecting components for your design, it can seem as though there are unlimited options. Not only are there millions of components, but there are a plethora of vendors and distributors from which to choose. And, embarking on an unguided electronic parts search can be overwhelming, time-consuming, and costly in terms of wasted work hours. However, by first knowing the options (shown below) that are available, a more focused and efficient approach to component sourcing and procurement can be developed.
PCB Component Sourcing Options
The options for sourcing components are as follows:
- Option 1: Individual component search
This is the most inefficient type of component search and should be used only for hard to find components.
- Option 2: Manufacturer component search
This can be a useful and direct option for experienced designers that are familiar with the types and ranges of components that a specific company makes. Furthermore, the manufacturer is typically the best source for information about its components. However, for most designs, this search will not be able to source all of the components required.
- Option 3: PCB software library
Most PCB design packages include component libraries. These have the advantage of not only including component information, but also including schematic symbols and PCB footprints that can easily be added to designs. However, even the best of these are limited and you will often have to either upload design data and images or create them from scratch for uncommon or special components.
- Option 4: Internet component database
The most extensive sources for components are online component databases. These tools contain components and data from many manufacturers and, in some cases, are linked with vendors and distributors to facilitate acquisition.
PCB Procurement Options
There are three options for acquiring your components:
- Option 1: Buying directly from the manufacturer
Acquiring components directly from the manufacturer can be advantageous. For example, prices may be lower; however, many electronic component manufacturers only utilize distributors. Even if available, you will need to order and wait for shipments from multiple suppliers, which can wreak havoc on your development schedule.
- Option 2: Buying from a vendor or distributor
Utilizing a single vendor is indeed possible and allows you to easily assemble design kits and perform component price comparisons. However, the responsibility of ensuring component availability rests with you.
- Option 3: Using a PCBA turnkey manufacturing service
Component sourcing and procurement can be a time-consuming process to stay informed of component availabilities, verify supply chain security, and ensure reliable sources are used. Turnkey PCBA manufacturing alleviates these responsibilities, as your contract manufacturer (CM) is responsible for procuring your components.
With the number of options available, it is necessary that a set of guidelines be established to optimize the PCB component procurement process.
How to Best Meet PCB Component Procurement Objectives
There is no single sourcing and/or procurement option that is the best for all PCBA designs. However, by creating and following a PCB component procurement strategy, a set of guidelines (as presented below) can be formulated. And, if followed, these guidelines can be used to assure that your procurement and sourcing process includes the necessary considerations that are best for your design.
|RECOMMENDED PCB SOURCING AND PROCUREMENT GUIDELINES|
|Design Attributes||Sourcing Option(s)||Procurement Option(s)|
|Small number of components||2, 3, 4||2, 3|
|Large number of components||3, 4||2, 3|
|Simple design||2, 3, 4||2, 3|
|Complex design||3, 4||2, 3|
|Upgrade or enhancement||2, 3, 4||2, 3|
|New and/or custom||3, 4||2, 3|
|Includes exotic component(s)||1, 2, 3, 4||1, 2, 3|
As shown in the table above, making use of your design software’s library is always a good choice. Additionally, using a PCBA turnkey manufacturing service is probably the best procurement choice. However, if you do acquire components yourself, you should try to use a single vendor, if possible.
In most cases, your PCB component sourcing process can benefit from the use of an internet library database to quickly and easily search millions of components and acquire design data that is seamlessly uploadable for the most popular ECAD applications. If you’re looking for CAD models for common components, Ultra Librarian helps by compiling all your sourcing and CAD information in one place.