How do the chips work in phones

System-on-a-Chip (SoC): Processors for mobile devices

Qualcomm Snapdragon 865
Image: When it comes to the speed and performance of smartphones or tablets, one often speaks of the "processor" or "the CPU". Strictly speaking, however, it is not that simple. Instead of simple processors, modern mobile devices contain entire systems, so-called systems-on-a-chip (SoCs), which are much more complex than a single processor. But what exactly is in a SoC?

Modern smartphones and tablets are essentially small computers. In order to be able to use such diverse functions as apps, WiFi, videos, music and games on the mobile phone, the small everyday companions need very similar components as their desktop counterparts, i.e. CPU, RAM, graphics unit, modem, etc. - and all of this in much less space. Because the devices are not only smaller, they also require a long-lasting - and therefore large - battery. SoCs do just that: the most important system components are combined on a small chip.

What's in a SoC? The components at a glance

Qualcomm Snapdragon 865
Image: To better understand how an SoC works, it helps to take a look at the most important components. Note, however, that not all of the following parts appear in all SoCs. The world of single-chip systems is diverse and includes numerous different manufacturers and developers with different product ranges for all conceivable uses, such as in smartphones, smartwatches and other wearables, smart TVs, IoT applications, cars, receivers and much more. Therefore, only some of the most important components are mentioned below:

  • The CPU
    CPU stands for Central Processing Unit and designates the main processor. This can contain one or more cores and controls all important device functions. Multiprocessor systems are also possible.
  • More processors
    To relieve the CPU, many SoCs contain additional processors to which individual commands and computing processes can be outsourced.
  • The GPU
    The graphics processor enables, for example, complex 3D games to be displayed on a tablet or smartphone. As with CPUs, there are many different GPU architectures.
  • Cache memory and RAM
    Like a computer, smartphones and tablets also need a memory to run programs (program memory) and to store and edit files (data memory).
  • modem
    Some SoCs have a modem, for example numerous Snapdragon models from Qualcomm with a built-in LTE or 5G modem. Integrated components for WiFi or Bluetooth are also common.

ARM architecture: a model for success

arm logo
Image: poor

One-chip systems
with ARM architecture
Most smartphone and tablet SoCs are based on the so-called ARM architecture, a particularly energy-saving processor design that was introduced by the British computer company Acorn in the early 1980s and has been continuously developed since then. ARM (Acorn RISC Machine, where RISC means Reduced Instruction Set Computer, in German for example: Computer (processor) with a reduced instruction set) itself does not manufacture chips, but only sells licenses to manufacturers who then use them to develop their own chips. British customers include such well-known companies as Samsung, MediaTek and IBM. You can find an overview of the ARM architecture in our guide to the ARM processor architecture.

System performance: It also depends on the software

As we have seen, it is not just the CPU that is decisive for performance and speed, but the SoC as a whole. SoCs are much more than just the main processor. In addition to it, countless sub-processors also play an important role in the overall performance of the system: graphics and audio processors, encryption and decryption units, general hardware accelerators - they all relieve the CPU and enable faster overall performance.

What should not be forgotten in addition to the hardware specifications: The software always plays a decisive role in real performance. The figures given by the manufacturers are theoretical maximum values ‚Äč‚Äčthat can only be achieved if the software is executed perfectly. Even the most powerful SoC is of little use if the software doesn't play along.

Qualcomm Snapdragon

Qualcomm headquarters
Image: Qualcomm The US semiconductor manufacturer and supplier for mobile communications companies Qualcomm (short for "Agonyity Communication ") was founded by Irwin Jacobs and Andrew Viterbi in 1985. Its product range includes software and various hardware, especially SoCs from the Snapdragon series, which are developed in-house but manufactured by the Taiwanese group TSMC (Taiwan Semiconductor Manufacturing Company).

Qualcomm's main processor component is based on the ARM microprocessor architecture. The first SoC with the model number MSM7225 was presented in 2007 and has been continuously developed since then, with the names changing frequently. Model numbers that begin with MSM or QSD indicate an integrated cellular modem; those that begin with APQ do not have one. In addition, Qualcomm's SoCs were classified as System 1 (S1) through System 4 (S4), with S1 SoCs used for simple mass-produced goods and S4 SoCs used for high-end devices. There was a further subdivision within the various systems. For example, the categories "Play", "Plus", "Pro" and "Prime" were created for the S4 class.

In the meantime, for the sake of simplicity, only "Snapdragon", followed by a three-digit number, is used for the name. Snapdragon 200 stands for the lower performance range, Snapdragon 800 for the upper. However, the model designation indicating an integrated modem does not have to be dispensed with. For example, behind the Snapdragon 810 is the MSM8994 model. The latest model from Qualcomm is the 5G SoC Snapdragon 888, but it does not have AI components / neural network hardware. However, these can be found in other, similarly powerful Snapdragon SoCs.


MediaTek Dimensity 1200 SoC
Image: MediaTek MediaTek (MTK) is a factory-free Taiwanese company founded in 1997 that mostly manufactures microcontrollers based on the ARM architecture. Initially a division of the Taiwanese company United Microelectronics Corporation (UMC), which was itself a spin-off from the state Industrial Technology Research Institute (ITRI) founded in 1980, MTK was finally spun off and became an independent company. Like Qualcomm, MTK has its SoCs produced by other companies such as TSMC. In the 3rd quarter of 2020, MTK ousted Qualcomm as the largest seller of smartphone chips for the first time, which was accompanied by a market share of 31 percent.

The first chip was named MT6205 and belonged to the group of ARM7 processor cores with 32-bit RISC ARMv5 architecture. The latest series, the SoC flagship Dimensity, is used in various devices such as smartphones, tablets, smartwatches, smart TVs and for IoT applications. It has a Cortex-A78 processor core on the 64-bit RISC architecture ARMv8.2-A.

As is now common practice with other manufacturers, MTK equips some of its newer SoCs with hardware for AI applications. The Dimensity 1200 (MT6893) is not one of them initially. The Dimensity 1000+ (MT6889Z / CZA), Dimensity 1000 (MT6889), Dimensity 820 (MT6875) and Dimensity 800U (MT6853V / TNZA resp. MT6853T).


Intel Atom x5 / x7 SoC for tablets (diagram)
Image: Intel Intel's SoC series of chips presented in 2011 were given the well-known brand name "Atom" and are intended for use in particularly inexpensive and energy-saving systems such as smartphones and tablets. The x86 microprocessor architecture is primarily used as the instruction set; later, in the same year, an x64 instruction set followed with the Diamondville generation. Intel's ultra-low-voltage microprocessors have been known as "Atom" since 2008.

With the microarchitecture generation "Silvermont", four SoC families were announced in 2013, one of which contains the two SoCs "Merrifield" and "Moorefield", which were intended for smartphones and were also released in 2014 (Atom Z34 and Z35 series ). However, they do not play a role for use in smartphones and therefore Intel consequently stopped development.

The SoC platform launched in 2015 with the code name "SoFIA" ("Smart or Feature Phone with Intel Architecture") - for Smartphones Atom x3 processors - was discontinued in 2016 with the announcement of a restructuring. Intel's smartphone SoCs, which exclusively used the CISC (Complex Instruction Set Computer) architecture, were also produced by TSMC. For other mobile devices such as tablets, Intel provides SoCs from the Airmont family (14 nm die-shrink of the Silvermont generation). These include processors of the x5 and x7 series. The last news for the time being that made people sit up and take notice came from Intel's Pat Gelsinger himself. He announced that he wanted to win Apple as a customer, so that with the M1 SoC, Intel chips would find their way back into Apple's computers.

Normally, where there is Intel, AMD (Advanced Micro Devices) is not far away either. However, AMD has completely abandoned the business with SoCs for smartphones and is now only developing them for other hardware such as PCs and embedded systems. According to rumors, AMD is planning its own SoC for smartphones with the ARM Cortex-A microprocessor architecture (TSMC's 5 nm production) with the Ryzen C7. Whether AMD or Intel can establish themselves again as a real alternative in the field of smartphone processors, however, is in the stars with a view to the extremely strong competition from Mediatek, Apple and Qualcomm.


iPhone 12 with A14 Bionic SoC
Image: Apple The basis for Apple's (modern) smartphones is the A series of so-called Apple-designed processors (also called Apple Silicon). Development began in 2007, before various series were introduced, with the first SoC "APL0098" (also "8900B" or "S5L8900"), which was built into Apple's first iPhone. The SoC belonged to the group of ARM11 processor cores with 32-bit RISC ARMv6 architecture. Other series got, inter alia. the letters S, T, W, H, U and M. With the Apple M1 SoC, Apple is bringing the first laptop with ARM architecture onto the market.

The development of the A series began in 2014 with the 32-bit package-on-package (PoP) SoC A4 manufactured by Samsung. It was first used in the first generation iPad and a short time later for the iPhone 4 and other devices; the A7 presented in 2013 was the first 64-bit PoP SoC. After no extra names were given up to the A9, the A10 was given the name "Fusion" before "Bionic" was introduced from the A11 series. Since the A10, Apple has had its chips produced exclusively by TSMC, previously by Samsung or mixed in parts by Samsung and TSMC.

The latest SoC, A14 Bionic, is installed in the iPhone 12 and the fourth generation of the iPad Air. It is based on the 64-bit ARMv8.5-A architecture, which - like all ARM processors - uses the reduced instruction set (RISC). Two things should be mentioned as special features. On the one hand, there is dedicated neural network hardware (NPU: Neural Processin Unit, a form of AI hardware acceleration) that Apple calls the "16-core neural engine". This should create 11 trillion instructions per second. On the other hand, the SoC has special second-generation units for accelerating matrix calculations for AI applications.

Further guides at a glance

News about SoC