5 tips for selecting printed circuit board connectors

Five tips for selecting printed circuit board connectors

Today’s connector users must consider numerous parameters when selecting the right connector for their application. Here’s a checklist of what to look for.

Today there are many more aspects than in the past when looking for a suitable connector.

The selection options and diversity continue to increase in the field of connectors as well. Whereas a few years ago only temperature resistance and the number of mating cycles were important for the selection of connectors, topics such as contact coatings, soldering methods, or even packaging forms for safe transport suitable for automated machines are now also relevant for the user.

This article gives users of PCB connectors five tips for selecting the right connector for the application.

1. technical parameters:

First, you should know the technical requirements of your application so that you can find the right connector. These parameters are: Pitch, soldering method, rated voltage, rated current, mating cycles, temperature range, board spacing, contact geometry and hole diameter of the solder lugs.

Based on these specifications, you can search the websites of connector manufacturers and distributors on your own. However, as soon as further specifications or even customer-specific designs are required, you should contact the connector manufacturer directly.

The timing of the contact also plays an important role. The earlier in the development process the user contacts the manufacturer, the higher the chance that a standardized connector or only a slightly modified version can be used.

2. The right design-in time:

For many designers of printed circuit boards, the arrangement of the active components, such as microcontroller, transistor or diode, initially plays the decisive role. Passive components such as capacitors, resistors or even connectors are often placed at the back of the development process. However, this approach harbors great potential for conflict.

For your next connector design-in: Consider active and passive components

If you do not take passive components into account during development, the PCB design will ultimately become much more complicated and costly in many cases. This is because it is often no longer possible to use standard connectors; instead, customer-specific connectors have to be developed first.

For the manufacturer, customer-specific connectors often mean a modification of the production machines or the production of customer-specific devices and tools. Depending on the degree of customization, this can result in costs ranging from a few hundred to several tens of thousands of US$ or €uros.

For prototype quantities, however, these tool adaptations are not economical. This is why the timing for considering connectors and also all other passive components in the development process is so important. After all, the profitability of the customer’s project should also remain within bounds.

3. the right packaging:

In addition to the standardized cardboard box, which is often used for THT connectors, packaging can also be used for automated assembly. These packaging options are tape & reel and the bar magazine. The bar magazine is often used in the prototype phase or for smaller quantities. The tape & reel packaging option, on the other hand, is more likely to be used for series production and thus also for higher quantities.

In most cases, bar magazines are geometrically limited to a length of approx. 500 mm. Tape & reel are determined only by the height of the connector and the chamber spacing of the components in the belt. This means that significantly more connectors can be transported via the Tape & Reel packaging option and assembled on the PCB.

4. Supply chains:

Many manufacturers of PCB connectors are located in the Far East. Due to the current shortage of raw materials and the associated long delivery times, there is a great opportunity for smaller manufacturers from Europe, too. Many PCB assemblers and also PCB developers are currently trying to find alternatives to connectors from the Far East via online cross-references.

However, users should take into account the differences in quality, such as gold plating. While flash gold with a very thin gold plating layer is applied in most cases in the Far East, electroplating companies from Europe often work with a minimum layer thickness of 0.2 µm gold.

The problem of delivery delays can be eliminated in the future by strengthening also America as a production location and thus also suppliers from the Northern American regions: e.g. 7-530671-2 / A115640-ND as CONN EDGE DUAL FMALE 20POS 0.125 in combination with 583859-9 / 583859-9-ND as CONN CARDEDGE HSG 20POS .156 BLK of TE Connectivity AMP Connectors with CoO: USA.

To this end, Digi-Key offers not only short delivery times, but also a high level of expertise and quality both in standard articles and can help in the development of customized special solutions.

5. partners:

As a final user tip, you should select a reliable partner that operates on a long-term basis. The manufacturer should reliably deliver high quality. But also the combination of contact materials must fit. For the contact partners, the contact coatings should be of the same material type if possible.

A combination of tin-plated pin contact and gold-plated socket contact is possible, but not beneficial to a long system life due to contact corrosion (electrochemical voltage series). In any case, it is better to use only tin-plated or pure gold-plated contacts in an application.

The magic triangle of cost – time – performance

The customer has a great deal of freedom in selecting the appropriate PCB connector and packaging option. However, the magic triangle of cost, time and performance plays a crucial role.

This magic triangle is currently best served by connectors from America and Europe. This is because, in addition to short delivery times, excellent quality and a reasonable price structure can also be achieved.

With the uncertain CoViD situation in China this Countries of Origin could also be avoided to secure future supply chains.