Renesas SOTB Enables Energy Harvesting Options for MCUs

Most modern circuit designs include energy efficiency as a major focus. Low energy consumption assures two considerable advantages in DC applications: smaller battery size and cell longevity. The natural step up is to eliminate the battery or its scheduled replacement. Is it possible?

Renesas Electronics developed its SOTB process technology for MCUs with the goal of providing circuit options for extended battery life or battery-less operation in low voltage applications. Both active and standby currents are reduced without sacrificing performance, thereby avoiding the normal tradeoff between the two that is associated with either large or small conventional silicon geometries.

This technology provides a promising, maintenance-free solution for IOT applications that may have experienced energy constraints, before. Given that IOT networks often rely on small batteries and energy harvesting sources that supply a low current level, the RE0x MCU series is well suited to work with sensors common in smart homes, passive monitoring systems, portable devices, wearables, etc.

The Renesas RE family of MCUs includes an energy harvesting control (EHC) circuit that enables direct connections to energy collection sources such as piezo, solar, vibration, etc. The EHC protects against start-up inrush currents and also controls the charging of any optional rechargeable batteries or supercaps.

The RE family is currently represented on the Digi-key site by the RE01 series: [click here Integrated Circuits (ICs) | Embedded - Microcontrollers | DigiKey ]. Product Index > Integrated Circuits (ICs) > Embedded Microcontrollers > Manufacturer Filter: Renesas + Series Filter RExx

For all of our other microcontroller products, please use the following link: [click here Integrated Circuits (ICs) | Embedded - Microcontrollers | DigiKey ], Product Index > Integrated Circuits > Embedded Microcontrollers, or search from our home page: [click here ].

Interested in trying out an RE family microcontroller as part of an evaluation board? Ask our technical staff to set up a quote for EK-RE01 [click here ].


SOTB = Silicon on Thin Buried Oxide; a proprietary Renesas transistor technology.
SOI = Silicon on Insulator; the wafer type upon which SOTB is developed.
EHC = Energy Harvesting Circuitry; embedded circuitry within RE MCU products.
BOX = Buried Oxide; a thin oxide layer in SOTB technology that minimizes leakage current and parasitic capacitance.

For an in-depth look at the SOTB structure and a possible SOTB/Bulk CMOX hybrid, here are a few Renesas graphics:

Further reading:

Renesas Energy Harvesting Application Note [click here ].

Renesas RE Family [click here ].