Masayuki Hanada
Masayuki Hanada
Principal Product Marketing Specialist
Published: August 2, 2022

General-purpose microcontrollers (MCUs) operating at 100 MHz or higher have reduced the operating voltage in recent years, with many products supporting only 3V supply voltage. Although operating MCUs at low voltage are fine for some applications, customers developing high-voltage products, such as home appliances and industrial products, very often request for MCUs to support a 5V power supply. However, 100 MHz or higher RX general-purpose MCUs are currently only available with a 3V power supply, and there are high technical and cost barriers to commercialize a MCU supporting 5V power supply. The new RX660 MCU is developed to support a 5V power supply meeting the customers’ needs.

High voltage switching noise in inverter control and other applications is generated while using 3V MCUs, causing noise effects on the input signal to the AD converter resulting in large AD conversion errors. This leads to increased accuracy errors in software operations, which results in poor control efficiency and responsiveness. False detection of voltage levels in hardware can also increase and lead to malfunctions in system operation. As a result, customers have to take countermeasures by placing external components (inductors, capacitors, etc.) to reduce the noise effects.

One consumer electronics customer once told us that the cost of noise tolerant components is higher than the cost of the MCU. Although the cost of a single 3V MCU may be lower than that of a 5V MCU, what about the total cost, including noise suppression components?

Changing your system to a 5V MCU will help to reduce costs.

In addition to cost reduction, the RX660 has numerous features besides its 5V power supply support.

  1. The high-precision built-in oscillator circuit eliminates the need for an external oscillator circuit (accuracy = less than ±1.0%)
  2. The maximum number of effective pins is 134 in a 144-pin package. This is a significant increase of more than 10% over the conventional number of pins.
  3. Well-proven inverter control functions (high-performance 16-bit timer, high-speed 12-bit AD converter)
  4. The first CAN FD integrated in the RX series, enabling large-capacity, high-speed communication, which was an issue with CAN2.0.
  5. Easily scale development by replacing RX general-purpose products with compatible peripheral function and pin layout.

There are applications such as UPS that use MCUs in both system control and inverter control respectively, due to concerns of noise effects, etc. A new winning combination – Online Uninterruptible Power Supply (UPS) – combining recommended analog and power management devices for power conversion circuits from Renesas, while utilizing RX660's high noise tolerance is prepared for your reference. The system control + power conversion section (inverter, buck regulator, boost regulator for battery, and PFC), which used to be comprised of two MCUs, can now be controlled by a single RX660 MCU simplifying the design. This system also allows remote monitoring by connecting to Bluetooth (DA14531) using the abundant communication functions. Learn more by visiting the winning combination page.

If you face any noise-related issues, RX660 MCUs can solve your problems. Start evaluation immediately with the RX660 development board.

View this short video to learn more about RX660. Alternatively, visit for more information.

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High Performance and Noise-Tolerant RX660 MCU for 5V Power Supply

Learn more about RX660 MCU which is the first general-purpose microcontroller to deliver superior noise tolerance for 5V power supply. RX660 enables scaling of development by increasing the effective number of GPIO pins by 10% compared to RX210. Also, the embedded CAN FD controller enables high-speed and large-volume data communication facilitating real-time control between devices.