New Army of Analog Chips in China

Development of Domestic Signal Chain Chips

In the field of analog chips, there are not many domestic players at present, and many local manufacturers have been listed. However, the coverage of product categories of domestic analog chips is still relatively limited. According to the functional division, analog chips can be divided into power management chips, signal chain chips, RF chips and other devices. In the whole analog chip market, power management and signal chain chips account for nearly 70% of the market share.

Benefiting from a longer life cycle and relatively scattered application scenarios, the market of signal chain chips has developed well in recent years, and the industrial scale is also growing steadily. Signal chain chips are mainly used to send/receive, convert, amplify and filter analog signals. The working principle of a complete signal chain is as follows: actual signals in the real world, such as sound, image, temperature, electromagnetic waves, optical signals, etc., are detected from sensors, and these natural signals are converted into analog electrical signals, which are amplified by amplifiers, and then converted into digital signals by ADC converters. After being processed by MCU, CPU or DSP, on the one hand, they are converted into analog signals by DAC, and on the other hand, they are interconnected by various connecting chips. It can be said that the signal chain is the basis for electronic devices to realize perception and control. Among signal chain chips, amplifiers and comparators (linear products) are the categories with the highest market share. As the area of digital chips becomes smaller and smaller, the signal chain chips that are matched with them will develop towards miniaturization, low power consumption and high performance driven by more new technologies.

Different from digital chips, which emphasize computing performance and pursue computing speed, it is necessary to keep competitive advantage by pursuing advanced manufacturing processes. More importantly, analog chips can achieve a balance among other parameters, such as high signal-to-noise ratio, low distortion, high reliability and stability. Once the design goal of products is realized, they will have a long life span, and the life cycle of most products can be up to more than 10 years. Longevity creates a product with low churn rate that lasts for decades, and also reduces the need for maintenance research and development, freeing up funds for reinvestment or distribution.


The Battle for Talents is Crucial to the Development of Chip Enterprises

Analog chips also have high requirements for talents, and are highly dependent on experience. Designers need to be familiar not only with circuit design and wafer manufacturing process, but also with the electrical and physical characteristics of most components. Besides, EDA tools have limited effect on the design and simulation of analog chips, so they can't design with EDA tools as well as digital chips, and analog chips are more dependent on manual design. At least 10 years of experience is required for an excellent analog design engineer.

The high experience dependence and the long life cycle of products create the high barrier characteristics of analog chips, and the diversity of products also makes it difficult for competitors to enter the market whose precursor has a 20-year leading edge and keep up with its development pace. There is a certain gap between domestic analog chip enterprises and international analog chip manufacturers in terms of market position, overall technical strength, sales scale and product variety completeness.


Catch up with Foreign Technology and Fabricate China's Own Signal Chain Chip

As a result of the Sino-US trade war, the high-end chip field has become an important bottleneck field, among which high-precision signal chain products and signal chain SOC products are of Class I product category with a big gap between domestic companies and European and American companies among the chip categories. Under such historical background, Suzhou Legendsemi Technology Co., Ltd., a new player in analog field, was born quietly in 2020. A group of R&D personnel who are committed to narrowing the gap between China's high-precision signal chain products and the international market and have many years of experience in analog-related technologies gathered together. Relying on many years of working experience in international big factories, Legendsemi started an extraordinary journey.
At present, Legendsemi's main products have two directions. One is ADC, DAC, voltage reference and high-precision operational amplifier related to high-precision signal chain, which mainly replaces the high-precision signal chain products of international brands; the other is the signal chain SOC/MCU based on arm core integrated high-precision analog products, which focuses on the high integration of vertical market segments to help customers reduce costs, reduce power consumption and miniaturize signal chain products.

In 2021, Legendsemi overcame the difficulties in productivity and technology, and successfully launched the first 24-bit ΣΔADCAFE - LH001-91 and LH001-99 in July 2021. LH 001-91 is a medical-grade analog front-end specially developed for ECG signal acquisition, which integrates 24-bit Δ ADC, programmable gain amplifier and AFE with right leg driving, conductive shedding monitoring and other functions. The product has excellent performance indexes, including input reference noise of 2.9 μVpp, common mode rejection ratio of 120 dB and internal reference temperature excursion of 16 ppm/℃; the static power consumption is 0.1 μW, and all the core indexes have reached the level of international brands. Furthermore, the overall performance is better than that of similar products of international manufacturers, and it has been professionally evaluated by domestic medical customers. At present, it is a domestic chip that can rarely pass the medical test in China.

LH001-99 is an AFE for EEG detection. Based on LH001-91, the input reference noise is optimized by 1.02 μVpp (250 sps, gain 24). This chip has been adopted by many customers of EEG detection in China.

In March 2022, Legendsemi launched LH001-55, which integrates 24-bit ΣΔADC at output rate of 2.55 sps-30 Ksps, and integrates programmable gain amplifier, 12-bit DAC, temperature sensor, trans-impedance amplifier, excitation current source and 25 ppm/℃ reference source. It can be used in the fields of pressure detection, battery monitoring, temperature monitoring and DC detection. Many customers have gotten start with it.

In 2022, Legendsemi will launch 400G-800G optical module controller SOC chip, SOC chip based on ARM core integrated 24-bit SDADC and signal chain SOC chip based on ARM core integrated 16-bit SARADC in succession. At the same time, 12-bit-18-bit series SARADC chips will be launched, which will fill the domestic gap and be widely used in industrial and medical high-precision control testing and other fields.


There is still a long way to go for analog chips to catch up with the international advanced level. However, a journey of a thousand miles begins with a single step. Legendsemi will continue to invest in the field of analog high-precision signal chain and SOC, persist in its initial intention, and strive for the goal of catching up with the international advanced technology, so that Legendsemi will succeed in chip industry.