Backplane PCB: All You Need To Know About

February 21, 2023

By Gus Edwards

Regarding Backplane PCB, We have seen a rise in the use of integrated circuits and the adoption of top-notch electronic assembly technologies.

Additionally, electronic devices now call for high-speed development and signal processing. Consequently, we have seen the development of complex systems like backplane PCBs to support such functions.

But what’s a backplane PCB, is it different from a motherboard, and what are its applications? Well, for answers on backplane PCB, we got you covered.

What Is A Backplane Board

(Hard disk backplane)

A backplane is simply a group of connectors linked in parallel to form a computer bus. In other words, it’s a printed circuit board type with line cards or daughterboards for custom functions.

You can use it as a backbone to link different PCBs to develop a complete electronic system.

Generally, it carries boards and distributes functions like signal transmission and power supply. Surprisingly, it doesn’t carry out onboard processing like the motherboard.

However, you can employ plug-in cards on it for processing and storage purposes.

How is A Backplane Board Different from a Motherboard?

(Motherboard circuit components)

There are several differences between a motherboard and a backplane. Check them out below:

Basics

Generally, a motherboard is a PCB with the main computer components like RAM, a central processing unit, and input-output connectors.

Therefore, it’s the computer backbone through which the external and internal components connect.

On the other hand, a backplane is a PCB that carries out motherboard functionality except for the storage capabilities and onboard processing.

With a backplane, you’ll find components on an expansion adapter card.

Circuitry

A motherboard is a larger PCB with many circuits for its components’ primary function. Additionally, you’ll get several expansion slots for sound and video cards.

A motherboard will connect indirectly or directly to your PC components.

On the other hand, a backplane comes with interconnecting slots but without major chips. However, it might have power supply regulating circuits.

The backplane is designed with one bus style that interconnects the different cards.

Longevity

How long a motherboard will last isn’t consistent and will depend on several factors, including the environment, usage, and heat factor.

Additionally, the performance of a motherboard will depend on whether the technology is outdated or not.

Surprisingly, a motherboard won’t work with outdated technology. You can only upgrade your motherboard by purchasing a new one.

However, the quality of a backplane depends on the connector quality. You’ll find certain connectors withstanding thousands of removals and insertions.

Usage

We all know what a motherboard does. It is the backbone of your electronic device, the link between the different components.

Therefore, it’s the central hub where you connect other devices.

From there, you can control the other components or accept inputs. Additionally, you can provide outputs.

However, a backplane connects different PCBs. You’ll find them mainly in microcomputers and high-reliability applications. Most people prefer using backplanes to cables since they don’t experience flexing problems.

Backplane and Motherboard comparison chart

Backplane	Motherboard
It’s a PCB with the features of a motherboard but without storage components and onboard processing.	A computer backbone that links all the other components
There is an expansion adapter to hold motherboard components. You plug this adapter into a slot	All the components aggregate on a single PCB or motherboard
Has a single bus style	It can optimize a system having several buses

Backplane Attributes

Backplanes undergo a different level of specialization that makes them unique. Consequently, they have the following attributes:

Thicker

Backplanes are designed with more layers than other PCBs. Additionally, they’re required to transit signals at very high speeds.

And since they support high-consumption cards, their copper layers must be thicker to offer enough current.

Heavier

As mentioned, backplanes are designed with heavier copper to provide enough current. Therefore, you’ll find them heavier than other PCBs.

Higher Heat Capacity

Since backplanes are heavier and thicker and transmit a lot of current, they have a higher heat capacity.

Many Drilling Holes

As mentioned, backplanes feature a more complex structure. Therefore, they have to achieve more signal transmission and electrical connections.

Surprisingly, this depends on having many drilling holes or buried vias. Consequently, you’ll find many drilling holes in a backplane for it to function well.

Backplane Assembly Focus

(Circuits on hard disk backplane)

Generally, backplanes are very complex and well-designed boards. Therefore, we expect special attention and complex technology to go into its design. Check out the fabrication focus below:

Reflow Soldering

Backplanes are heavier and thicker than other boards. Therefore, it becomes difficult to dissipate heat.

Surprisingly, it’ll take more time to cool after reflow soldering. Consequently, there is a need to strengthen the reflow soldering oven to allow the board enough time to cool.

Additionally, it would be best to use air cooling at the reflow soldering oven’s exit to speed up cooling.

Cleaning

As mentioned, backplanes are thicker and feature many drilling holes. Therefore, it’s common for working fluid to flow out.

We recommend cleaning the drilling holes using a high-pressure cleaner to remove the working fluid.

Layer Alignment

The higher drilling hole and layer count will make it difficult to obtain layer alignment. Therefore, you should employ care and high technology to manage layer alignment during fabrication.

Component Assembly

In the past, passive components were mainly placed on backplanes for reliability concerns. However, we have seen many active components being designed on backplanes.

Therefore, we recommend that assemblers use smaller resistors and capacitors. Additionally, they should employ larger PCB assembly platforms.

Applications of Backplanes

(Computer code components)

Blackpanes are mainly used as backbones in systems like control panels for military systems and computing.

Many people prefer them as alternatives to cables thanks to their higher reliability. We can attribute this to them being more static than cables.

Surprisingly, cables must be flexed whenever you remove a card. Consequently, you’ll find them reducing the component’s lifespan.

On the contrary, backplanes have a longer lifespan and will increase your connection’s lifespan.

Backplane Form factors

Backplanes always have form factors that determine their chassis size. Additionally, it’ll determine the power connection the board uses. Check out the common form factors below:

Advanced (AT): These can be small or complete. The complete backplanes are 35 cm deep and 31 cm wide. However, small form factors are 33 cm deep and 22 cm wide. Surprisingly, IBM employed these factors to design personal computer backplanes.
Low Profile eXtension (LPX): These form factors are 33 cm deep and 23 cm wide. Western Digital used this form factor as an alternative to the advanced form factor.
Advanced Technology Extended (ATX): This option combines the LPX and advanced form factors. Here, you’ll get five different configurations and sizes: micro, mini, pico, nano, and standard.
Nex Low-Profile Extended (NLX): This alternative to the LPX mainly finds use in industrial applications. However, it’s designed with similar measurements to the LPX form factor.

FAQ

Are backplanes the same motherboards?

You’ll find a lot of similarities between a motherboard and a backplane. Both are printed circuit boards found in electronic devices.

However, there are differences, including that a backplane doesn’t have storage components and onboard processing.

How many types of Backplanes do we have?

We have active and passive backplanes. Active backplanes come with motherboard circuitry and bus control. However, they lack complex processor elements like cache, chipset, and CPU.

On the other hand, passive backplanes don’t have active bus-driving circuitry. However, they have chipsets to buffer signals to the slots.

What are backplanes in a router?

Surprisingly, backplanes are available in network devices like switches and routers. They connect physically between power and data buses and the interface cards.

Conclusion

In conclusion, a backplane is simply a PCB that carries out motherboard functionality except for the storage capabilities and onboard processing.

Therefore, it comes with little or no active circuitry. You’ll find backplanes in microcomputers and some industrial applications. Surprisingly, it has a higher lifespan and is thus preferable to cables.

We hope that you now understand more about backplanes and their uses. Feel free to ask for further clarifications.