Renesas claims the new memory is the world’s first embedded 2T-MONOS (2 Transistors-Metal Oxide Nitride Oxide Silicon) Flash memory based on 65nm SOTB technology. It is available in a 1.5 MB capacity. In combination with a new circuit technology that reduces the power consumption of peripheral circuits on Flash, Renesas has recorded read energy as low as 0.22 picojoules per bit (pJ/bit) at 64 MHz – among the world’s lowest levels for embedded flash memory on an MCU.
The new low-power technique for cutting the power used by peripheral circuits reduces energy consumption when sensing data in memory and also reduces the amount of transmission energy consumed when read data is transmitted externally. These two advances in parallel substantially reduce energy consumption when reading data from the memory.
SOTB-based technology has already been used in Renesas’ R7F0E embedded controller, which is designed for energy harvesting applications. The SOTB process technology reduces power consumption in active and standby states. Power consumption in these two states had previously been a trade-off - lower power consumption in one usually meant higher power consumption in the other. The new technology reduces power usage when reading data from the flash memory.
In contrast to non-SOTB 2T-MONOS flash memory, which requires a memory read current of about 50 µA/MHz, read current is reduced to approximately 6 µA/MHz. The new technology also contributes to a low-active read current of 20 µA/MHz on the R7F0E.
Renesas will present these results on June 12 at the 2019 Symposia on VLSI Technology and Circuits in Kyoto, Japan.