Renesas adds RL78/G21 MCU for appliance system control

Renesas has introduced the RL78/G21, a new 16-bit microcontroller aimed at system control in appliances such as air conditioners, refrigerators, washing machines and microwave ovens, alongside an expanded RL78/G23 lineup with additional capacitive-touch channels for HMI applications.

Renesas states the RL78/G21 achieves an operating current of 34 μA/MHz, which it describes as nearly half that of its existing RL78/G13 MCU products. The company attributes this to low-power technologies developed across the RL78 family, which it says has previously achieved top scores in the ULPMark-PeripheralProfile benchmark.

The device carries an ESD tolerance of ±4 kV HBM (Human Body Model), a figure Renesas says contributes to higher reliability during manufacturing, assembly and operation. This ESD rating applies to the RL78/G21 only, not the RL78/G23 variants covered in the same announcement.

The RL78/G21 adds a UARTA communication interface, which Renesas describes as an upgrade over the RL78/G13 intended to support system expansion such as additional sensors. Renesas states the new device is pin and functionally compatible with the existing RL78/G13 and RL78/G23, which it says allows existing designs to transition with minimal redesign.

Other features include an integrated high-speed on-chip oscillator with ±1.0% accuracy and 4KB of data flash, which Renesas says removes the need for an external oscillator and EEPROM and so reduces bill-of-materials costs. The company also cites security features including flash read protection, a flash shield window, Unique ID and Customer ID, along with self-diagnostic functionality enabled by an IEC 60730-compliant self-test library. The MCU has a specified operating voltage range of 1.6V to 5.5V.

Expanded touch sensing on RL78/G23

Separately, Renesas has added the RL78/G23 (R7F104G) variant with expanded capacitive-touch sensing. Compared with the existing RL78/G23 (R7F100G), which offers 14 touch channels in its 44-pin package and 16 channels in its 48-pin package, the new variant increases this to 24 and 25 channels respectively. Renesas says common touch peripheral functionality and its QE for Capacitive Touch development tool are shared across the RL78, RX and RA families.

Renesas states the RL78/G21 and RL78/G23 products are available now, with development support through its Smart Configurator software and Fast Prototyping Board. The company cites suggested resale pricing, based on a 10,000-unit quantity, of US$0.56 for the 128KB/44-pin LQFP RL78/G21 and US$0.77 for the 256KB/44-pin LQFP variant; Renesas notes this pricing is for reference only and that actual quotations require contacting a sales representative or distributor.

Renesas cites Gartner data to claim the No. 1 global market share position in 16-bit MCUs for 2025, attributing the figure to a March 2026 Gartner report on semiconductor market share by end market.