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Home > Products > Integrated Circuits (ICs) > Embedded > Microcontrollers

Renesas R5F121BCGNA#20

Name: R5F121BCGNA#20
Brand: Renesas
SKU: R5F121BCGNA#20
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: R5F121BCGNA#20

Manufacturer:: Renesas

Category:: Microcontrollers

Package:: 32-WFQFN Exposed Pad

Datasheet:: R5F121BCGNA#20.pdf

Description:: MCU:RL78

Quantity:: RFQ Add To RFQ list

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Inventory:1,220

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Product details

Overview

R5F121BCGNA#20 from Renesas Electronics is a 32-pin, 32 KB flash, 2 KB RAM RL78/G16 16-bit microcontroller with integrated capacitive touch sensing (15-channel CTSU), 10-bit A/D converter (11 channels), real-time clock (99-year calendar), and industrial-grade temperature range (−40°C to +105°C). It operates from a single 2.4–5.5 V supply and supports ultra-low-power STOP/HALT modes for battery-powered HMI and sensor control applications.

For engineers reviewing the R5F121BCGNA#20 datasheet, R5F121BCGNA#20 pinout, R5F121BCGNA#20 application, or R5F121BCGNA#20 equivalent, key selection considerations include its HWQFN-32 (5 × 5 mm, 0.5 mm pitch) package, 32 KB code flash with 1 KB data flash, 16-bit timer array (8 channels), and dual I²C/Simplified I²C support for industrial human-machine interface and embedded control designs.

Technical Context

The R5F121BCGNA#20 implements the RL78 CPU core-a CISC architecture with 3-stage pipeline-delivering minimum instruction execution times from 0.0625 μs (@16 MHz high-speed on-chip oscillator) to 30.5 μs (@32.768 kHz subsystem clock). Its memory subsystem includes 32 KB code flash (1 KB block size), 1 KB data flash (512 B block, 1M rewrite cycles), and 2 KB on-chip RAM.

Peripheral integration centers on system-level responsiveness and low-power operation: it features a 12-bit interval timer, watchdog timer with dedicated low-speed oscillator, real-time clock with alarm and correction, 16-bit timer array (8 channels), and hardware-accelerated capacitive touch sensing unit supporting self- and mutual-capacitance configurations up to 16 keys.

Key Specifications

Parameter	Value and Actual Design Meaning
Core	RL78 16-bit CISC CPU with 3-stage pipeline
Flash Memory	32 KB code flash; enables firmware storage and field updates without external memory
Data Flash	1 KB data flash with 32-bit rewrite unit; stores calibration data or user settings non-volatilely
RAM	2 KB on-chip RAM; sufficient for real-time control stacks and touch-sensing buffers
Operating Voltage	2.4–5.5 V single supply; compatible with standard industrial and battery-backed systems
Temperature Range	−40°C to +105°C (G-grade); certified for industrial ambient conditions
A/D Converter	10-bit resolution, 11 input channels; supports analog sensor interfacing with internal reference (0.815 V)
Capacitive Touch	15-channel CTSU; enables robust, low-power touch buttons/sliders without external ICs

Pinout & Package

Package: HWQFN-32 (5.0 × 5.0 mm, 0.5 mm pitch), exposed die pad (requires thermal pad connection to PCB ground plane).

Pin/Terminal	Circuit Role	Design Meaning
P00	UART0 TX / Serial output	Primary debug and communication interface; supports bootloader and host connectivity
P01	UART0 RX / Analog input ANI0	Full-duplex UART channel with analog sensing capability for hybrid signal acquisition
P125	Reset input / Interrupt INTP1 / VCOUT0	Active-low reset with glitch filtering; dual-function pin for system initialization and voltage monitoring
VDD / VSS	Power supply / Ground	Dedicated power/ground pairs minimize noise coupling in mixed-signal operation
P02	Touch sense TSCAP / ANI1 / PCLBUZ0	Direct connection to touch electrode; integrates charge-transfer sensing and buzzer drive
P41	RTC1HZ / TS13 / I²C SCL20	Real-time clock output and touch channel; enables time-stamped HMI events and multi-interface sharing
P60 / P61	I²C SCLA0 / SDAA0	Dedicated I²C bus pins supporting standard and fast-mode (400 kHz) peripheral expansion
P10 / P11	INTP8 / INTP9 / TxD1 / RxD1	Secondary UART with interrupt capability; allows concurrent serial communication and event handling

Key Features

Feature	Design Value
Low-power STOP/HALT modes	Reduces current consumption to sub-μA levels while preserving RAM and register state for rapid wake-up
Hardware CTSU engine	Offloads touch processing from CPU; enables <10 ms scan time for 15-key panels with noise immunity
On-chip high-speed oscillator	16 MHz ±1.0% accuracy (−20°C to +85°C); eliminates external crystal for cost-sensitive designs
Background data flash writes	Not supported-requires code flash execution suspension during data flash programming
Peripheral I/O redirection	Enables dynamic remapping of serial, timer, and interrupt functions to alternate pins without layout change
Industrial temp grade (G)	Qualified for continuous operation at +105°C ambient; suitable for sealed enclosures and motor-control environments

Applications

Home Appliance Control Panel	Industrial Sensor Node
Use Scenario: Touch-enabled microwave oven or washing machine front panel with LED feedback and motor control. IC Role / Device Role / Timing Role: Main system controller executing UI logic, driving buzzer (PCLBUZ0), reading touch inputs (CTSU), and managing appliance motors via PWM timers. Use Value: Integrated CTSU and 16-bit timers eliminate external touch controllers and timing ICs, reducing BOM count by ≥3 components.	Use Scenario: DIN-rail mounted temperature/humidity sensor node with RS-485 backhaul and local display. IC Role / Device Role / Timing Role: Data acquisition hub-reading analog sensors (ANI0–ANI10), timestamping readings via RTC, and formatting packets for UART-to-RS485 bridge. Use Value: 10-bit A/D with internal reference and −40°C to +105°C operation ensure accurate, drift-free measurements across harsh factory floors.
Smart Thermostat Interface	Medical Patient Monitor Frontend
Use Scenario: Wall-mounted HVAC controller with capacitive slider, ambient light sensing, and BLE co-processor interface. IC Role / Device Role / Timing Role: HMI processor handling touch gestures, ADC-based light/temperature sampling, and SPI/I²C communication with wireless module. Use Value: 15-channel CTSU supports multi-gesture sliders and proximity wake-up, while 32 KB flash accommodates secure OTA update stack.	Use Scenario: Bedside vital sign monitor with ECG lead-off detection, button interface, and audible alerts. IC Role / Device Role / Timing Role: Safety-critical frontend controller-managing analog front-end biasing, touch buttons, buzzer alarms (PCLBUZ0), and real-time clock for event logging. Use Value: G-grade temperature rating and on-chip BCD correction ensure reliable timestamping and alarm triggering under clinical environmental variations.

Home Appliance Control Panel

Industrial Sensor Node

Use Scenario: Touch-enabled microwave oven or washing machine front panel with LED feedback and motor control.

IC Role / Device Role / Timing Role: Main system controller executing UI logic, driving buzzer (PCLBUZ0), reading touch inputs (CTSU), and managing appliance motors via PWM timers.

Use Value: Integrated CTSU and 16-bit timers eliminate external touch controllers and timing ICs, reducing BOM count by ≥3 components.

Use Scenario: DIN-rail mounted temperature/humidity sensor node with RS-485 backhaul and local display.

IC Role / Device Role / Timing Role: Data acquisition hub-reading analog sensors (ANI0–ANI10), timestamping readings via RTC, and formatting packets for UART-to-RS485 bridge.

Use Value: 10-bit A/D with internal reference and −40°C to +105°C operation ensure accurate, drift-free measurements across harsh factory floors.

Smart Thermostat Interface

Medical Patient Monitor Frontend

Use Scenario: Wall-mounted HVAC controller with capacitive slider, ambient light sensing, and BLE co-processor interface.

IC Role / Device Role / Timing Role: HMI processor handling touch gestures, ADC-based light/temperature sampling, and SPI/I²C communication with wireless module.

Use Value: 15-channel CTSU supports multi-gesture sliders and proximity wake-up, while 32 KB flash accommodates secure OTA update stack.

Use Scenario: Bedside vital sign monitor with ECG lead-off detection, button interface, and audible alerts.

IC Role / Device Role / Timing Role: Safety-critical frontend controller-managing analog front-end biasing, touch buttons, buzzer alarms (PCLBUZ0), and real-time clock for event logging.

Use Value: G-grade temperature rating and on-chip BCD correction ensure reliable timestamping and alarm triggering under clinical environmental variations.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
R5F121BCMNA#20	M-grade variant: extended temperature range (−40°C to +125°C); identical pinout, memory, and peripherals	Suitable for under-hood automotive or high-temp industrial enclosures where >+105°C ambient occurs	Select R5F121BCMNA#20 only if full +125°C operation is required; otherwise R5F121BCGNA#20 offers cost advantage.
R5F121BCAFP#50	LQFP-32 package (7 × 7 mm, 0.8 mm pitch); same electrical specs but different thermal/mechanical footprint	Better suited for manual assembly, prototyping, or legacy PCBs designed for LQFP	Choose R5F121BCAFP#50 when HWQFN reflow capability is unavailable or board space permits larger footprint.

Compared with R5F121BCMNA#20 and R5F121BCAFP#50, the R5F121BCGNA#20 provides optimal balance of industrial temperature compliance, compact HWQFN packaging, and cost efficiency for volume HMI and sensor-control deployments-without sacrificing peripheral richness or flash capacity.

Availability

R5F121BCGNA#20 is available at Aetrix Electronics and suitable for industrial HMI interfaces, smart sensor nodes, and medical device frontends requiring stable component supply and long-term lifecycle assurance.

Supply support for R5F121BCGNA#20 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, and power solutions for industrial, automotive, and IoT markets.

The RL78/G16 product line delivers ultra-low-power 16-bit MCUs optimized for cost-sensitive, battery-operated, and industrial HMI applications-with integrated touch, precision analog, and robust real-time control capabilities.

FAQ

What is the maximum operating frequency and clock source flexibility of the R5F121BCGNA#20?

The R5F121BCGNA#20 supports up to 16 MHz operation using its on-chip high-speed oscillator, selectable at 1, 2, 4, 8, or 16 MHz with ±1.0% accuracy (−20°C to +85°C). It also accepts external crystals (X1/X2) or clocks (EXCLK) up to 20 MHz, and includes a 32.768 kHz subsystem clock for RTC and ultra-low-power modes. This flexibility allows the R5F121BCGNA#20 to adapt to both precision timing and energy-constrained use cases without external clock components.

Does the R5F121BCGNA#20 support background data flash programming while executing code from flash?

No, the R5F121BCGNA#20 does not support background operation (BGO) for data flash writes. During data flash rewriting, instruction execution from code flash memory is halted. The R5F121BCGNA#20 requires careful state management-such as copying critical routines to RAM-before initiating data flash updates to maintain system responsiveness. This behavior is documented in the R5F121BCGNA#20 datasheet Section 1.1 "Features".

How many capacitive touch channels does the R5F121BCGNA#20 support, and what configuration options are available?

The R5F121BCGNA#20 integrates a 15-channel Capacitive Touch Sensing Unit (CTSU) supporting both self-capacitance (15 independent keys) and mutual-capacitance (up to 16 keys in matrix configuration) modes. Pins P02 (TSCAP) and P03–P07, P16–P17, P20–P23, P41–P43 are designated for touch sensing. The R5F121BCGNA#20's CTSU includes hardware acceleration, noise suppression, and automatic drift compensation-enabling robust touch performance in noisy industrial environments without CPU overhead.

What serial communication interfaces are available on the R5F121BCGNA#20, and how are they allocated across pins?

The R5F121BCGNA#20 provides three UART channels, three Simplified SPI (CSI) channels, three Simplified I²C (SIIC) channels, and one full I²C channel. Dedicated pins include P00/P01 (UART0), P04/P03 (UART1), P10/P11 (UART2), P60/P61 (I²C0), and P41/P02 (I²C2). Multiplexing is managed via Peripheral I/O Redirection Registers (PIOR), allowing dynamic assignment of serial functions to alternate pins-giving the R5F121BCGNA#20 high routing flexibility in dense PCB layouts.

Is the R5F121BCGNA#20 pin-compatible with other RL78/G16 variants such as the R5F1214CANA#20 or R5F1217CANA#20?

No, the R5F121BCGNA#20 is not pin-compatible with R5F1214CANA#20 (16-pin HWQFN) or R5F1217CANA#20 (24-pin HWQFN). While all belong to the RL78/G16 family and share architectural consistency, they differ in pin count, package dimensions, and peripheral pin mapping. The R5F121BCGNA#20 is exclusively a 32-pin HWQFN device with 32 KB flash; substituting lower-pin-count variants would require PCB redesign. Always verify pinout against Table 1-6 in the R5F121BCGNA#20 datasheet before migration.

R5F121BCGNA#20 Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Package/Case:: 32-WFQFN Exposed Pad

Series:: RL78/G16

Packaging:: Tray

Product Status:: Last Time Buy

Programmable:: -

Core Processor:: RL78

Core Size:: 16-Bit

Speed:: 16MHz

Connectivity:: CSI, I2C, SPI, UART/USART

Peripherals:: Capacitive Touch, POR, PWM, Voltage Detect, WDT

Number of I/O:: 29

Program Memory Size:: 32KB (32K x 8)

Program Memory Type:: FLASH

EEPROM Size:: 1K x 8

RAM Size:: 2K x 8

Voltage - Supply (Vcc/Vdd):: 2.4V ~ 5.5V

Data Converters:: A/D 11x8/10b

Oscillator Type:: External, Internal

Operating Temperature:: -40°C ~ 105°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:

R5F121BCGNA#20 FAQ

1.How can I place an order for R5F121BCGNA#20 through Aetrix?

Please submit a Request for Quotation (RFQ) for R5F121BCGNA#20 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for R5F121BCGNA#20 reliable?

The price and inventory of R5F121BCGNA#20 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for R5F121BCGNA#20 is usually 5 days.

3.What payment methods are accepted for R5F121BCGNA#20?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for R5F121BCGNA#20 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for R5F121BCGNA#20?

R5F121BCGNA#20 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your R5F121BCGNA#20 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for R5F121BCGNA#20?

For technical support, including R5F121BCGNA#20 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your R5F121BCGNA#20 requirements.

6.How does Aetrix verify that R5F121BCGNA#20 is sourced from the original manufacturer or authorized distributors?

All R5F121BCGNA#20 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that R5F121BCGNA#20 meets industry standards.

7.What is the process for return or replacement of R5F121BCGNA#20?

All R5F121BCGNA#20 units undergo pre-shipment inspection (PSI). If there is an issue with R5F121BCGNA#20, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The R5F121BCGNA#20 part is unused and in its original packaging.

Return procedure for R5F121BCGNA#20:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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