What Is A Ball Grid Array And What Is It Used For?

Printed circuit boards, often referred to as PCBs, are the performance drivers of electronic circuits and nowadays, these are used in most electric devices. How these boards perform and how stable they are will depend on the layout of the connected components and how they are assembled.

There are several different ways that these components can be attached, these are referred to as arrays. Over the last few years, ball grid arrays (BGAs) have become more popular thanks to the number of benefits of these packages.

In this guide, we’re going to look in more detail at what ball grid arrays are, why they are used and how.

What is a ball grid array?

A ball grid array is a surface mount package that is used for integrated circuits (ICs) and they are used to mount devices onto PCBs. For example, mounting a small device like a microprocessor directly onto the printed circuit board. These arrays have grown in popularity as they provide more pins than other types of packages.

They have conducting and insulating layers which are usually made with thin copper foil and bonded together with epoxy resin. In order to conduct electrical signals from the circuit board, BGAs use solder balls which, as the name suggests, are arranged in a grid pattern on the package.

These types of packages were introduced in the 1990s, and unlike other arrays, the solder balls are placed on the solder pads of the PCB rather than the pins. This way, they can be evenly spaced apart, reducing the risk of the elements fusing together when the board is heated.

What are ball grid arrays used for?

As well as serving the primary function of permanently mounting devices onto printed circuit boards, there are a number of other reasons that BGAs are used in the way they are. Below, we’ve outlined five other ways these packages are used, including the following:

Facilitating high-density connections

Because BGAs provide more connections than many other types of surface mount packages, they facilitate a better overall design and take up less space on the PCB. This increases functionality and improves performance.

Creating a smaller product

One of the top uses for BGAs is to ensure high-density connections whilst also keeping the end product lightweight and small in size. After all, no one wants heavy or bulky electrical items, particularly in the era of tablets and smartphones.

Tackling heating issues

As ball grid arrays are able to better dissipate the heat coming from the integrated circuit, they can help to reduce the risk of overheating in the PCB. This has helped to tackle outdated overheating issues.

Providing excellent performance

We’ve briefly touched on how BGAs can improve performance, but let’s now look at this in more detail. Because the solder balls are closer together and laid out more neatly, the chance of the signal being distorted is reduced. This allows these arrays to provide excellent, high-speed performance.

Improving readability

Finally, on some of the other types of packages, the pins being used are more fragile. This means they can be damaged fairly easily. Whereas, ball grid arrays rely on the solder balls being connected to the pads. Therefore, making these stronger, more reliable and improving readability.

Are there any downsides to choosing BGAs?

Now we’ve looked at the different ways ball grid arrays are used and the benefits these can have on electrical devices, let’s take a look at the other side of the coin. While there are lots of reasons to use these packages over others, they are not without their downsides.

One of the biggest issues is that thanks to the small size of these packages, they are difficult to inspect; something which must be done at the end of the assembly process. This means that equipment like microscopes and X-ray machines must be used to overcome this key challenge.

Not only this, but the cost of the soldering equipment can be very expensive.

All that being said, experts agree that the benefits of BGAs far outweigh these larger upfront costs. Though more money will be required immediately, the time, resources and money saved on these processes and components more than makes up for this.