Renesas R5F121BCGNA#40

Overview

R5F121BCGNA#40 from Renesas Electronics is a 32-pin, 32 KB flash, 2 KB RAM RL78/G16 16-bit microcontroller in HWQFN-32 (5 × 5 mm, 0.5-mm pitch) package, operating from 2.4–5.5 V with industrial-grade temperature range (−40°C to +105°C), integrated capacitive touch sensing unit (15 channels), and real-time clock with calendar function - deployed in smart appliance control panels and industrial HMI modules.

For engineers reviewing the R5F121BCGNA#40 datasheet, R5F121BCGNA#40 pinout, R5F121BCGNA#40 application, or R5F121BCGNA#40 equivalent, key selection criteria include its 32-pin HWQFN thermal performance, 15-channel CTSU support for button/slider interfaces, RTC calendar accuracy over −40°C to +105°C, and dual SPI/I²C/UART serial interface concurrency without bus contention.

Technical Context

The R5F121BCGNA#40 implements the RL78 CPU core with 3-stage pipeline CISC architecture, supporting instruction execution times from 0.0625 μs (@16 MHz high-speed on-chip oscillator) to 30.5 μs (@32.768 kHz subsystem clock). It integrates a dedicated low-speed on-chip oscillator for watchdog and RTC operation independent of main clock domain.

Its peripheral set includes eight 16-bit timers, one 12-bit interval timer, one 99-year RTC with alarm and correction, 10-bit A/D converter with up to 11 analog inputs, two comparators with selectable reference sources, and hardware-accelerated capacitive touch sensing using self- and mutual-capacitance methods across 15 pins.

Key Specifications

Pinout & Package

Package: HWQFN-32 (5.0 × 5.0 mm, 0.5-mm pitch) with exposed die pad - requires PCB thermal pad connection for reliable operation at +105°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit microcontroller applications.

Compared with R5F121BCMNA#40 and R5F121BCAFP#50, the R5F121BCGNA#40 delivers optimal balance of industrial temperature compliance, compact HWQFN packaging, and full peripheral feature set - making it the default choice for new designs targeting −40°C to +105°C operation with space-constrained layouts.

Availability

R5F121BCGNA#40 is available at Aetrix Electronics and suitable for smart appliance control panels, industrial HMI modules, and energy meter user interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for R5F121BCGNA#40 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 is a global semiconductor leader specializing in microcontrollers, analog, power, and SoC solutions for industrial, automotive, and enterprise markets.

The RL78/G16 product line targets cost-sensitive, low-power embedded applications requiring integrated analog peripherals, capacitive touch, and industrial temperature resilience - optimized for appliance, building automation, and sensor edge nodes.

FAQ

What is the maximum operating frequency and clock source configuration for the R5F121BCGNA#40?

The R5F121BCGNA#40 supports up to 16 MHz operation using its on-chip high-speed oscillator, configurable to 16/8/4/2/1 MHz with ±1.0% accuracy across −20°C to +85°C. External crystal (X1/X2) or resonator options are also supported for higher precision timing-critical applications. The R5F121BCGNA#40 does not require external clock components for basic operation.

Does the R5F121BCGNA#40 support in-system programming and debug interfaces?

Yes, the R5F121BCGNA#40 includes an on-chip debug function compatible with Renesas E2 emulator and standard SWD/JTAG interfaces. It supports full in-system programming via the dedicated TOOLRxD/TOOLTxD pins or dedicated debug connector, enabling firmware updates and real-time debugging without removing the R5F121BCGNA#40 from the target board.

How many capacitive touch channels does the R5F121BCGNA#40 support, and what configurations are available?

The R5F121BCGNA#40 integrates a dedicated Capacitive Touch Sensing Unit (CTSU) supporting up to 15 self-capacitance channels or up to 16 mutual-capacitance keys using matrix configuration. All 15 CTSU channels are accessible on dedicated pins (e.g., P02/TSCAP, P03–P07, P16–P17, P20–P23, P41–P43), and configuration is managed entirely in firmware without external components.

What is the data flash endurance and rewrite unit size for the R5F121BCGNA#40?

The R5F121BCGNA#40 includes 1 KB of data flash memory organized in 512-byte blocks, with a minimum rewrite unit of 32 bits. It guarantees 1,000,000 write/erase cycles (typical) across the full VDD range of 2.4–5.5 V, enabling reliable storage of calibration coefficients, device IDs, or user preferences without wear-leveling overhead.

Is the R5F121BCGNA#40 pin-compatible with other RL78/G16 variants in the same package?

Yes, the R5F121BCGNA#40 is fully pin-compatible with all other RL78/G16 devices in the HWQFN-32 package (e.g., R5F121BAGNA#40, R5F121BCMNA#40), sharing identical pin mapping, power sequencing, and peripheral routing. Firmware and PCB layout can be reused across memory and temperature grade variants without modification.