Renesas introduces a low power embedded flash technology based on SOTB technology to achieve energy collection without battery power supply

Renesas electronics co., ltd. announced that it has launched a new type of embedded flash memory with low power consumption technology based on 65nm SOTB technology, which can provide 1.5mb capacity. It is the industry's first embedded 2t-monos flash memory based on 65nm SOTB technology.By introducing new circuit technology to reduce the power consumption of peripheral circuits in flash, the reading power consumption at 64 MHz working frequency is as low as 0.22 pJ/bit -- the lowest level of embedded flash in the industry on the MCU.Low power technologies for peripheral circuits include :(1) reducing energy consumption when detecting data in memory;(2) reduce transmission energy consumption when sending read data to the outside world.This advanced technology helps to dramatically reduce the energy consumption when reading data in storage.

Renesas presented the test results at the 2019 annual VLSI and circuit technology symposium (June 9-14, 2019) in Kyoto, Japan, on June 12.

The new SOTB based technology has been used in the rissa R7F0E embedded controller, which is specially used for energy acquisition applications.Renesas' unique SOTB technology significantly reduces power consumption at work and standby.In general, the power consumption in these two states increases and decreases with each other: that is, the lower power consumption of one means the higher power consumption of the other.The new technology dramatically reduces power consumption when reading data from flash memory.Compared with non-sotb 2t-monos flash (about 50 micron /MHz reading current), the new technology can achieve A reading current of only about 6 micron /MHz, which is equivalent to 0.22 pJ/bit reading energy consumption and reaches the lowest level of MCU embedded flash energy consumption.The new technology also helps achieve A low effective reading current of 20 microns per MHz on the R7F0E, the best in the industry.

Key features of new embedded flash technology:

Low power 2T-MONOS flash memory suitable for SOTB process

The SOTB 2t-monos embedded flash memory has a dual transistor structure containing an electrical isolation element.Different from the single transistor structure, there is no negative voltage during the reading operation, which reduces the power consumption when reading data.In addition, MONOS USES fewer masks in production than other memory processes and can store data using a discrete charge capture scheme, allowing for low power consumption and high rewrite reliability without increasing production costs.

Used for ultra-low energy sensing amplifier circuit and voltage regulator circuit technology

Most of the energy consumption in the reading process of memory occurs in the sensing operation of identifying data and the output of identifying data to the outside.To solve this problem, the single-terminal sensor amplifier significantly reduces the bit line precharge energy during the sensing operation, and USES a new charge transfer technology to improve the precharge speed and energy efficiency.In addition, the newly developed voltage regulator circuit technology USES leakage monitoring to control the reference voltage of the sensing amplifier in an optimal intermittent manner, making it consume energy in a constant way.These advanced technologies not only greatly reduce energy consumption, but also accelerate sensing operations.

Circuit technology that drastically reduces the power consumption of data transmission

One of the characteristics of SOTB process is to minimize transistor threshold (Vth) fluctuations.The new technology makes use of this advantage to realize data transmission with extremely small voltage amplitude.When the read data is sent externally, the technology significantly reduces the energy consumption of transmission.

Renesas is accelerating the development of the "smart society" by helping to make endpoint devices smarter.Renesas believes that eliminating the need for battery replacement is a necessary step toward this goal.At the same time, renesas will continue to contribute to the development of environmentally friendly smart societies.

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(note 1) MONOS: metal nitrous oxide silicon oxide.This technology has enabled renesas to excel in EEPROM, security MCU and other product areas for more than 20 years.MONOS technology is used in embedded flash memory in renesas MCU products.