With the rapid popularization of smart homes, health care, the Internet of Things, new energy vehicles, and other fields, the global demand for MCU is getting higher and higher, especially for low power consumption, customization, and specific peripherals. need.
Most of the topics in the semiconductor industry in the past two years have been about microcontrollers, which have a wide range of applications and are one of the essential chips for almost all intelligent applications. According to the classification of bits, MCU mainly includes 8/16/32/64 bits. According to different application requirements, MCUs with different bits need to be used to play a role.
Source: Internet
Application Fields of MCU with Different Bits
The number of MCU bits represents the width of data processed by its CPU at one time. Simply put, the larger the number of bits, the stronger the MCU processing capability. The main fields of MCU with different digits are different.
The consumer electronics field has relatively low requirements for MCU specifications, generally with 8 bits, which are mainly used in drones, self-balancing vehicles, the Internet of Things, and small home appliances such as sweeping robots. The indicators of industrial control MCU are more stringent, mostly 32 bits, and are used in factory automation, robotics, power transmission and grid power supply, electrical motor control, smart city and smart building automation, etc. In addition, the most demanding application field for evaluating the performance of MCU chips is automobiles. Automotive MCU needs to meet the requirements of both function and safety.
Major Manufacturers in the MCU Market
In the 8-bit MCU market, Microchip, STMicroelectronics, etc. have a relatively high market share. Microchip occupies more than 30% of the share, the main product is the PIC16 series 8-bit single-chip microcomputer, CPU adopting a RISC structure. It emphasizes cost-saving optimal design, and most chips have their compatible FLASH program memory. Fast running speed, low price, low power consumption, and good anti-interference make it occupy a firm position in the market. Another high share is STMicroelectronics' low-power 8-bit MCU-STM8 series.
In addition to the STM8 series, ST's STM32 series microcontrollers also have a place in the 32-bit MCU market. Its STM32 MCU is based on the ARM core. In fact, the 32-Bit MCU of most MCU manufacturers are outsourced cores, and the main energy is devoted to the research and development of other parts. In addition to Renesas, it is mainly based on self-developed cores, supplemented by outsourced cores.
There is also a noteworthy semiconductor player. Texas Instruments, which mainly promotes analog products, has also launched a series of 32-bit microcontrollers represented by piccolo series microprocessors.
The automotive market is currently the most concerned area of major manufacturers. New energy vehicles are the future trend, at least for a long time, it is one of the most promising fields. The global automotive MCU manufacturers are mainly concentrated in the six international IDM manufacturers of STMicroelectronics, Renesas, NXP, Infineon, Microchip Technology, and Texas Instruments, with a market share of over 80%.
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Updated Iterations for Microcontrollers
Semiconductor technology continues to iterate in finer detail, and MCUs also need to keep pace with the times. Some start from the core and switch from the Arm Cortex-M core to the RISC-V core. Some choose to integrate AI accelerators to make the MCU more intelligent. Another is to integrate a new type of memory.
MCU integrates CPU, SRAM, non-volatile memory, and dedicated peripherals. The most common forms of memory mainly include eDRAM, SRAM volatile memory, flash memory, and EEPROM non-volatile memory. Among them, integrated flash memory is an important feature of MCU. Although the emergence of flash memory has solved the problem of the difficulty of erasing program data in ROM in the past, as time goes by, flash memory has gradually become one of the bottlenecks restricting MCU performance improvement and power consumption reduction.
The manufacturing process of flash memory cannot keep up with the development of MCU. MCU has started to move towards 28nm, but the manufacturing process of flash memory is difficult to expand below 40nm, and it is difficult to integrate into very complex high-K metal gate technology. In automotive applications, the flash memory integrated into the on-board MCU has too few rewritable times, with each write and erase cycle, the tunnel oxide in the floating gate NOR cell will degrade and the leakage will increase, which will accelerate the aging of the flash memory, making it unsuitable as data memory.
Therefore, more and more MCU manufacturers choose to integrate new types of memory, such as phase change memory (PCM), magnetic RAM (MRAM), and resistive memory (RRAM).
Resistive Random Access Memory (ReRAM or RRAM)
Infineon has announced the introduction of TSMC's RRAM non-volatile memory (NVM) technology into Infineon's next-generation AURIX MCUs.
RRAM is a storage technology with the simplest structure. Working by changing the resistance of a dielectric, applying just the right voltage across it creates tiny conductive filaments that allow current to flow, with reversible switching between high and low resistance states.
Since RRAM can combine the reading and writing speed of DRAM with the non-volatility of SSD, it has the advantages of high erasing and writing speed, strong durability, and the ability to store multiple bits of data in a single storage unit. Plus, the power consumption of RRAM is much lower than that of flash.
Source: Infineon
Infineon revealed that AURIX TC3x has become the preferred automotive microcontroller for many applications. This time, AURIX TC4x based on TSMC RRAM technology improves ASIL-D performance, artificial intelligence functions, and the latest network interfaces (including 10Base T1S Ethernet and CAN) -XL) further expands on this success, AURIX TC4x MCUs combine performance scaling with the latest trends in virtualization, security and network functions to support next-generation software-defined vehicles and new E/E architectures for the automotive field The introduction of RRAM laid the groundwork.
Phase-change RAM (PCRAM)
Another major MCU manufacturer, STMicroelectronics, is an early researcher in phase-change memory (PCM), especially for automotive applications.
The principle of Phase-change RAM, or PCRAM, is to switch the phase-change material between a low-resistance crystalline (conductive) state and a high-resistance amorphous (non-conductive) state by changing the temperature.
According to pc.watch, among the production technologies after the 28nm generation, the first eNVM technology released by MCU manufacturers is ePCM. In 2018, STMicroelectronics announced that the technical architecture and performance standards of the 28nm FD-SOI automotive MCU with built-in ePCM began to provide major customers with MCU samples equipped with ePCM.
STMicroelectronics is the first manufacturer capable of integrating this non-volatile memory with 28nm FD-SOI technology and developing high-performance, low-power automotive MCUs.
Compared with other embedded memory technologies, PCM has the characteristics of low latency, write performance/data retention, long life, low power consumption, good radiation resistance, and high density.
Magnetic RAM (MRAM)
MRAM is a technology based on the tunneling magnetoresistance effect. It has the characteristics of non-volatility, unlimited read and write times, fast write speed, low power consumption and high integration of logic chips. The current mainstream MRAM technology is STT-MRAM, and the MCU manufacturer focusing on this technology is Renesas. Renesas announced at IEDM 2021 that it has confirmed that it has reduced power consumption and increased write operation speed on a 16nm FinFET logic process embedded STT-MRAM test chip.
Source: Renesas
Renesas has developed two technologies for MRAM, a self-terminating write scheme using slope pulses and simultaneous write bit number optimization technology. The aim is to improve performance and power consumption. The combination of these two technologies can reduce write energy by 72% and shorten write pulse application time by 50%.
Renesas' MCU integrated with STT-MRAM technology is mainly used in the field of Internet of Things. With the continuous advancement of artificial intelligence technology, it is necessary to use finer process nodes to manufacture MCUs. Renesas has developed circuit technology for STT-MRAM testing chips with fast read and write operations fabricated using a 22nm process.
No matter what kind of meomory technology, it is developed to meet the increasingly updated needs of the market. How to develop new equipment and materials required for emerging technologies is an issue that MCU manufacturers need to pay close attention to. We will wait and see which technology will stand out in the future.