If you are a sports fan, then you would probably agree there is nothing as exciting as the buildup to a championship sporting event. Take the Super Bowl, for example. During the weeks between the determination of the two teams slated to play and the actual game, there is virtually around the clock conversation from pundits, colleagues, friends, and family. And, of course, everyone knows what the outcome will be and is happy to share it with you. This is not unlike what happens when a promising new technology is on the horizon.
The speed of 5G?
The new 5G communications protocol is a good example. It is predicted that accelerating to the speed of 5G will not only improve wireless data transfer between devices but also aid the transition to IIoT for industrial production. As all electronic devices rely on the boards of which they are comprised, this means that PCBA development must also evolve to accommodate this new technology. Before looking at how best to develop your 5G PCB, let’s see exactly what all the excitement is about.
Why All the Buzz About 5G?
Perhaps, the best way to answer this question is to take a look at the history and evolution of wireless technology that has brought us to this point. Believe it or not, there was a time when cellular phones did not exist. The latter part of this period that immediately preceded the introduction of cellular phone technology is known as 0G or zero generation wireless technology. Mobile communication was available during this time; however, it was limited to mobile radiotelephony using devices like two-way walkie-talkies.
Beginning in the late 1970s and early 1980s, the first generation of cellular technology, 1G, based on the Advanced Mobile Phone Standard (AMPS) and Nordic Mobile Standard (NMT) was rolled out. Analog phones were used during this period for voice-only communication. With the advent of 2G in 1991 based on the Global System for Mobile communications (GSM) cellular phone usage began to gain the functionality that we are familiar with today. This includes SMS text messaging and digital data transmission. However, data rates were modest, at best, at around 236.8 kbps.
Over the past nearly two decades, there have been three other generational advances in wireless technology, 3G, 4G and 5G, which are listed and compared in the table below.
|Comparison of 3G, 4G, and 5G Wireless Technology|
|Technology||Data Speeds||Standards||Switching Technique(s)|
|3G||384 kbps||CDMA2000, UTMS, HSDPA, EVDO||Circuit (Voice)
|4G||≤ 1Gbps||LTE, WiMAX||Packet (Voice & Data)|
|5G||≤ 20Gbps (estimated)||5G NR||Packet (Voice & Data)|
As shown in the table above, the leap in data transfer rates expected with 5G is indeed something to get excited about. As we are transitioning towards 5G capability, companies that are already upgrading must ensure operability to older wireless technology; such as 4G and 3G in some places. Therefore, it is likely that 5G transfer rates will only be available in isolated areas, like individual cities, for the immediate future. This may appear to be a drawback for cross-country or global communications; however, it may also be a strength that will enable 5G to be fully leveraged for localized communications. An example is for smart factories that employ IIoT.
In deference to what some laymen may assume, 5G does not refer to the frequency or bandwidth of data and voice communications for the new wireless technology generation. In fact, there is not a single specific range of frequencies for 5G. Instead, there are three bands: low, mid and high. For low-band 5G, frequencies are below 5 GHz, which is slow, but can travel great distances. This enables utilization for older TV transmissions. Mid-band 5G operates from 1-10 GHz. This allows for wider channels, but less distance than low-band. However, most cellular phones and Wi-Fi devices operate in this range. Frequencies for high-band 5G range from 20-100 GHz, which is truly fast! The drawback, of course, is the transmission range which is approximately 800 ft.
Now that we have a better understanding of what 5G wireless technology is and why so many are excited about its arrival let’s take a look at what is needed to build boards to optimize its utilization.
Optimizing Your 5G PCB Development
As discussed above, 5G frequencies are quite varied and extend into the millimeter-wave range. And compared to high-band, the mid and low frequencies can be considered slow as they are orders of magnitude lower. However, for PCBA development, all 5G bands are considered high frequency. This means there are special considerations that must be taken into account for design and manufacturing; including high density interconnect (HDI) routing and DFM for high-speed digital signal transmission. These and other important issues that must be addressed to maximize signal strengths and minimize losses for 5G signals are listed below.
5G PCB Design and Manufacturing Optimization
- Synchronize channel pads for TX/RX devices
5G TX/RX chips are special components. Some of which contain channel pads that must be precisely aligned for proper operation. Therefore, it is imperative that these are manufactured with tight footprint tolerances.
- Utilize proper keepouts for antenna
Antennas must be impedance matched with traces to achieve maximum power transmission and reception. When keepouts are required they must aid in providing controlled impedance as well as provide the necessary clearance for EMI concerns.
- Choose BGAs for high pin count components
BGAs are typically preferable to minimize fanout as many 5G boards will be small and compact. However, you should also follow good routing guidelines for these devices.
- Use an accurate PCB impedance control calculation method
One of the most important parameters for high-speed PCBAs is impedance matching. And you should employ a PCB impedance control calculation technique that will yield results that meet your accuracy criteria.
- Select trace parameters based on impedance control
Copper weight, trace length, and width are all important and impact PCB signal integrity. For the best results, these should be selected based on impedance control, as much as possible.
- Select materials based on impedance
The materials of your PCB layout determine the impedance of your board; therefore, care must be taken to select materials that meet your high-speed PCB design criteria.
- Design to the process window centers of your CM’s DFM PCB tolerances
To help facilitate the best board build for your design that translates into reliable operation over the PCB lifetime you should focus your design choices at the center of PCB tolerances or process windows for your CM’s equipment.
5G wireless technology is not coming. It is here! There is a lot of buzz about how it will impact many industries and propel us to the next level in areas like IIoT. But to realize these goals requires that the boards utilized are developed to optimize the technology.
|Tempo's Custom PCB Manufacturing Service
At Tempo Automation, we lead the industry in building complex and compact boards fast; such as required for many 5G devices. We can also help you by building development boards for new electronics products.
And to help you get started on the best path, we furnish information for your DFM checks and enable you to easily view and download DRC files. If you’re an Altium Designer or Cadence Allegro user, you can simply add these files to your PCB design software. For Mentor Pads or other design packages, we furnish DRC information in other CAD formats and Excel.
If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on 5G PCBs or how to best design boards for this technology, contact us.