The concept of SoC or system on a chip has been one of the most listened to in the field of computing for several years, and in particular when we talk about devices such as mobile phones. But what exactly does it entail? Where is an SoC used? In this article we will review the definition of SoC and review how they have been used so far. We started!
Index of contents
- What is an SoC: definition of system on chip
- SoC example: Arm processors used in our mobile phones
- Advantages and disadvantages of using an SoC
- PC processors: are they also an SoC?
- Notable exceptions: Intel and AMD processors that are indisputable SoCs
- More examples of SoC uses
- Embedded systems
- Game consoles
- Raspberry Pi
- Final words and conclusion about what is an SoC
What is an SoC: definition of system on chip
Formally, an SoC is known as a chip that integrates all or most of the components necessary for the operation of a computer. Among them, a CPU will almost always be included, so we can talk about a processor that includes more components inside that would normally be relegated to external chips.
So, we can talk about SoC when we combine other parts to a CPU such as a graphics card, network modems, RAM memory or storage … or even when we simply add input / output parts such as USB or SATA control, lines PCI Express, etc. The great requirement is that they are parts that in a traditional PC architecture would be attributed to a separate chip, and not to the SoC itself.
That’s where this name comes from, because as we say SoC means system on a chip or system on a chip, making clear the unification it represents.
Once defined, what should be presented in the article is where an SoC will be used, which will mainly be in embedded systems or mobile devices. Later we explain what advantages an SoC can have, although intuitively we already realize that the fact of unifying the operation of the equipment on the same chip can imply energy, space and cost improvements.
SoC example: Arm processors used in our mobile phones
The most representative example of what an SoC is is in the Arm architecture chips used in our mobile phones as well as many other devices. In them, practically everything necessary for the operation of the device is integrated, doing everything in a very small space, and allowing to have the existing miniaturization in current mobiles.
Thus, in a typical mobile the number of chips that we find on its small plate is not very significant. We are going to take advantage of iFixit’s disassembly of any recent mobile, for example the OnePlus Nord, and see what components it has inside:
- Four Qualcomm power management and management chips for different tasks.
- Memory (8GB RAM) and storage (128GB) combination chip.
- Audio codec.
- Two Skyworks chips related to modem functions.
- Qualcomm Atheros chip with WiFi, Bluetooth 5, WPA3 and FM radio.
- And obviously the Snapdragon 865 5G SoC itself.
The Snapdragon 865 does less functions than normal, and even so we see how the mobile is left with very few chips inside.
Obviously, you would also have to consider the battery, the camera sensor, ports and connections, etc. But they are already parts that are not really attributable to the SoC itself.
The idea is more than clear, since the Snapdragon SoC is the one that has the responsibility of carrying most of the device’s tasks. But what are these tasks? We are going to break them down one by one for the case of the Snapdragon 888, since the previous 865 does not incorporate the modem inside and is an example of a “worst case”.
- Qualcomm Hexagon 780 processor (CPU) with LITTLE cores
- ISP (Image Signal Processor) Spectra 580
- Graphics card (GPU) Adreno 660
- Sensing Hub, which integrates the data from all the device’s sensors and processes it.
- Additional security coprocessor.
- Snapdragon X60 modem in charge of all 5G and radio frequency.
- FastConnect 6900, with WiFi 6 and 6E, and Bluetooth 5.2.
Advantages and disadvantages of using an SoC
Once the concept of system on chip has been thoroughly explained and one of the most representative examples presented, it is worth wondering, what advantages and disadvantages does the use of an SoC imply compared to having several separate chips?
Let’s start with the benefits. The first and the most fundamental is in the energy, economic and space saving that favors the fact of joining several functionalities in a single chip. And it is that having separate chips for the different functionalities of a device can suppose the following waste:
- Less economic expense in the manufacture of the chips itself, since making several is much more expensive than one to maintain a single function. Be careful, this advantage must be grasped with tweezers because it has been shown that in some cases integration is much more expensive,so it can also be treated as a drawback.
- If we combine all the functionalities in a single chip, we will surely save a good amount of space within the device, something that is critical in a mobile phone.
- Data buses, which are wiring after all,consume an amount of energy that we can save if we directly communicate each piece within the same chip.
All three points are really important on devices like mobile phones, so they must be kept in mind. But we have more advantages: concentrating execution on the chip itself is synonymous with additional performance and security .
And what disadvantages does it have? Basically, the cost of the development of the chip itself, which becomes much more complex, in addition to the fact that manufacturers will depend on the manufacturer of the SoC to a greater extent, because if a component is part of the system on chip and there is an implementation or supply problem, it will not they could just replace it. Sometimes what they can do is expand the capabilities of the SoC itself using external chips, which is a really good thing. For example, there are many mobiles whose SoC has 4GB of RAM memory that is later expanded by an external chip to reach the desired level.
Finally, it should be noted that they may not be suitable for energy-intensive applications, although if you continue reading the article you will see how there are high-performance SoCs that do not have this problem. Everything depends largely on the design, so it is difficult for the advantages and disadvantages that we have mentioned to be maintained in absolutely all cases.
PC processors: are they also an SoC?
Taking into account the definition that we have given you of SoC, it makes a lot of sense to consider to what extent a current PC processor is. In particular, we are going to analyze whether a current AMD Ryzen or Intel CPU can be considered an SoC or not.
In these CPUs, like many others, we not only have the processor itself inside, but we also have other parts that were previously carried on separate chips. Specifically, we are talking about the northbridge or north bridge, which integrates the memory controller and the PCIe lines, and that in older computers was part of the motherboard.
To this must be added the fact that most Intel Core CPUs and AMD Ryzen APUs have integrated graphics, another component typically used outside of the processor chip itself.
The great source of discrepancy is in the absence of essential components for operation such as memory. Many people consider that an SoC should have it all, that is, it should combine CPU, graphics and north bridge, south bridge and RAM. These last two parts are the ones that these processors do not have, lacking the USB, SATA and other drivers that are part of the chipset. This would cause that neither an AMD Ryzen or an ordinary Intel Core could be considered an SoC.
When Qualcomm Snapdragon first integrated 5G, they did so by taking the modem off the chip, and no one stopped calling them an SoC for it. The definition of system on chip is not so strict as to require that there be yes or yes a series of components in the device.
But, really, if we go to the definition of system on chip that we gave before, it could be considered that any modern processor is a SoC. In any case, in the current context it seems that it makes much more sense to refer to these CPUs as such and to use the name of SoC when some more components are integrated.
Notable exceptions: Intel and AMD processors that are indisputable SoCs
Now let’s move away from the controversial to discuss options from AMD and Intel that do fit perfectly with the definition of SoC. Specifically, two fairly representative examples: Intel Lakefield and AMD EPYC.
By the Lakefield band, this is a rather risky project for low-power processors for laptops due to its characteristics, such as that all parts of the chip are built stacked on top of each other. But what interests us is that it is effectively a SoC, by including everything necessary for operation (including RAM) within its own chip. This can be seen very well represented in the video above.
In the case of EPYC, we hide behind the fact that the company itself frequently uses the definition of System on chip ( source ), since in this case we are dealing with processors that do not integrate memory but do have all the functions of the chipset without exception, such as control of USB, SATA, PCIe, and more is on the chip itself, and only additional chips would be required for features like a GPU.
We can also see how laptop processors tend to have a deeper integration than a normal CPU, and fit better within the definition of SoC. We exemplify this with the AMD Ryzen 4000 in notebooks , known as Renoir, which are not limited to the basics of the southbridge, the cores and the iGPU, but also carry dedicated multimedia engines to accelerate the video codecs, etc.
More examples of SoC uses
It has already been clear that a system on chip is everywhere, but now we are going with more use cases that integrate more parts inside than a traditional processor.
Embedded systems are those that are used within a specific device such as a piece of machinery, an ATM, or in general any device that has a specific purpose and not a general use such as a traditional computer.
It is clear that here the miniaturization and concentration of all the parts of the system in a small space must be favored, making it more than ideal that a system on a chip be used for this purpose.
The most recent consoles also make use of an SoC that integrates a good part of the functionalities in a single chip, something understandable considering that they seek to be smaller than a normal desktop computer and consume less.
If we think about the last generation, the PS5 and Xbox Series X / S consoles use AMD SoCs that fit perfectly in the same category as computer APUs , again demonstrating how controversial the concept is, since most people call them SoCs. but no one calls a Ryzen APU that.
Finally, our last concrete example will be in the well-known Raspberry Pi, which as you know is a very small and low-cost computer intended for uses related to basic computing, science, industrial automation and robotics, etc. We all have in our heads that this is a team capable of doing a lot in a very small space, and this is thanks to the use of a SoC that concentrates a good part of the functionality. Let’s take as an example the Broadcom BCM2711 used in the Raspberry Pi 4 Model B, and some of its components:
- 4-core ARM Cortex A-72 64-bit 1.5GHz CPU.
- VideoCore VI (VC6) GPU with H.264 / H.265 encoding and decoding and video connection.
- I / O with a PCIe 2.0 bus, Gigabit Ethernet, USB 2.0, etc.
Final words and conclusion about what is an SoC
An SoC or system on chip is one of the most innovative concepts in computing. It basically consists of integrating in a single chip most of the necessary components in a system, or at least combining the CPU with several of these components. For example, if a processor has additional functions such as memory controllers, integrated graphics, etc., which in a traditional computer are attributed to several chips, then it would be a SoC.
Virtually any modern processor can be considered an SoC.
But the chips with which the SoC concept is most often used are those that also integrate other parts such as input / output controllers, RAM memory, etc. In particular, a mobile chip will have most of the functionality within the SoC itself, having to use a few more “big” chips, needing them only for more specific tasks.
If we go to the list of internals of a SoC par excellence like the Apple A14, we see how a lot of additional functionalities, coprocessors and more are integrated that totally complement what the CPU itself does. This can be image signal drivers, video encoders / decoders, RAM, storage, HDR processors, machine learning accelerators, GPUs, etc.
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In general, this type of SoC is used in all types of mobile or small devices, but as we say, it can be considered that they extend to the majority of processors on the planet. And it is that all this integration can be very beneficial, assuming significant savings in costs and energy consumption, as well as an increase in performance and reliability. The key is not to depend on external buses and to optimize the designs for a perfect integration between the components.