Available with 1.5 MB capacity, this product is, according to Renesas, the world’s first embedded 2T-MONOS (2 Transistors-Metal Oxide Nitride Oxide Silicon) flash memory based on 65nm SOTB technology.
With the addition of a new circuit technology that reduces the power consumption of the peripheral circuits on flash memory, Renesas achieves read energy as low as 0.22 picojoules per bit (pJ/bit) at an operating frequency of 64 MHz. This is among the world’s lowest levels for embedded flash memory on an MCU.
The new SOTB-based technology has already been implemented in the Renesas R7F0E embedded controller, which is intended specifically for energy harvesting applications. Renesas’ exclusive SOTB process technology reduces power consumption in both the active and standby states. Power consumption in these two states had previously been a tradeoff: Lower power consumption in one generally meant higher power consumption in the other.
The 2T-MONOS embedded flash memory using the SOTB process has a two-transistor structure comprising electrically isolated elements. Unlike a single-transistor structure, there is no need for negative voltage during read operation, and this reduces power consumption when reading data.
In contrast to non-SOTB 2T-MONOS flash memory, which requires a memory read current of about 50 µA/MHz, the read current is reduced to approximately 6 µA/MHz. This is equivalent to a read energy level of 0.22 pJ/bit.
MONOS also uses fewer masks during the production process, when compared to other memory devices; it is possible to store data with a discrete charge-trapping scheme also. This enables low power consumption and high rewrite reliability without increasing the production cost.
The new technology also contributes greatly to the achievement of a low-active read current of 20 µA/MHz on the R7F0E.