Renesas R5F10278DNA#U0

Overview

R5F10278DNA#U0 from Renesas Electronics is a 24-pin HWQFN-packaged RL78/G12 16-bit microcontroller designed for ultra-low-power embedded control in industrial applications. It integrates 8 KB code flash, 2 KB data flash, 512 B RAM, 10-bit A/D converter (11 channels), 2-channel DMA, and operates from 1.8 V to 5.5 V with true low-power consumption (63 μA/MHz). It supports UART, CSI, I²C interfaces and runs at up to 24 MHz using its high-accuracy ±1.0% on-chip oscillator - ideal for smart sensors and battery-powered industrial controllers.

For engineers reviewing the R5F10278DNA#U0 datasheet, R5F10278DNA#U0 pinout, R5F10278DNA#U0 application, or R5F10278DNA#U0 equivalent, this page delivers verified technical context, exact package mapping (HWQFN-24, 4 × 4 mm, 0.5-mm pitch), validated peripheral configuration, real-world use scenarios, and two confirmed alternative parts with documented functional and application-level differences.

Technical Context

The R5F10278DNA#U0 implements the RL78 CPU core with CISC architecture and 3-stage pipeline, enabling minimum instruction execution time of 0.04167 µs at 24 MHz. Its memory subsystem includes 8 KB code flash (1 KB block size), 2 KB data flash supporting background operation (BGO) and 1,000,000 write cycles, and 512 B on-chip RAM.

It features dual serial interfaces: one UART channel and two CSI (Simplified SPI) channels, plus two Simplified I²C channels - all enabled only in R5F102-series devices. Power management includes HALT, STOP, and SNOOZE modes, on-chip POR/LVD, and a 15 kHz low-speed on-chip oscillator for watchdog timing.

Key Specifications

Pinout & Package

Package: HWQFN-24, 4 × 4 mm body, 0.5-mm pitch, exposed die pad (to be connected to VSS).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microcontroller applications.

Compared with R5F1027ADNA#U0, the R5F10278DNA#U0 trades flash capacity for cost and density; compared with R5F10378DNA#U0, it adds critical reliability features (data flash, DMA, CRC) essential for field-updatable industrial firmware.

Availability

R5F10278DNA#U0 is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, PLC I/O modules, and energy metering subsystems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for R5F10278DNA#U0 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics Corporation is a global semiconductor leader delivering trusted embedded solutions for automotive, industrial, infrastructure, and IoT markets.

The RL78/G12 product line delivers ultra-low-power 16-bit MCUs optimized for cost-sensitive industrial control, sensor interfacing, and battery-operated equipment - balancing performance, integration, and energy efficiency.

FAQ

What is the maximum operating frequency and clock source accuracy of the R5F10278DNA#U0?

The R5F10278DNA#U0 supports up to 24 MHz operation using its high-speed on-chip oscillator, rated at ±1.0% accuracy over –20 to +85°C ambient temperature. External crystal oscillation up to 20 MHz is also supported via X1/X2 pins. This accuracy enables reliable UART communication at standard baud rates without external timing components, making the R5F10278DNA#U0 well-suited for industrial serial networks where timing stability is critical.

Does the R5F10278DNA#U0 include data flash memory, and what are its key characteristics?

Yes, the R5F10278DNA#U0 includes 2 KB of data flash memory. It supports background operation (BGO), allowing program execution from code flash while simultaneously rewriting data flash. Rated for 1,000,000 write cycles at VDD = 1.8–5.5 V, it enables robust field updates of calibration data, configuration parameters, or logging records - a capability absent in the R5F103-series alternatives and central to the R5F10278DNA#U0's role in maintainable industrial firmware.

How many analog input channels does the R5F10278DNA#U0 support, and what is the ADC resolution?

The R5F10278DNA#U0 integrates a 10-bit successive-approximation A/D converter with 11 input channels (ANI0–ANI3, ANI16–ANI22). It includes internal reference voltage (1.45 V) and a temperature sensor, supporting single-ended and differential measurements. This ADC configuration provides sufficient resolution and channel count for multi-sensor industrial monitoring - such as simultaneous temperature, voltage, and current sensing in motor control or power supply supervision applications using the R5F10278DNA#U0.

What serial communication interfaces are available on the R5F10278DNA#U0?

The R5F10278DNA#U0 provides one UART channel, two Simplified SPI (CSI) channels, and two Simplified I²C channels - all confirmed features exclusive to the R5F102 product family. These interfaces operate independently and can be assigned to different port pins via the Peripheral I/O Redirection Register (PIOR). This combination supports concurrent communication with UART-connected host processors, SPI-based ADCs or DACs, and I²C temperature/humidity sensors - a key differentiator versus the R5F10378DNA#U0, which lacks Simplified I²C and DMA.

What power-saving modes does the R5F10278DNA#U0 support, and how do they differ?

The R5F10278DNA#U0 supports HALT, STOP, and SNOOZE modes. HALT stops the CPU clock while preserving RAM and register contents; STOP disables all clocks including peripheral clocks and reduces current to ~0.52 μA; SNOOZE allows selected peripherals (e.g., UART, CSI) to remain active while the CPU sleeps, enabling wake-up on serial activity. These modes - combined with 63 μA/MHz active current - make the R5F10278DNA#U0 especially effective in intermittently active industrial edge devices that must balance responsiveness with multi-year battery life.