Renesas R5F121BAMNA#20

Overview

R5F121BAMNA#20 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 to 5.5 V with −40°C to +125°C industrial temperature range (M-grade), featuring 16-bit timer array (8 channels), 10-bit A/D converter (11-channel), capacitive touch sensing unit (15-channel), and real-time clock with calendar function.

For engineers reviewing the R5F121BAMNA#20 datasheet, R5F121BAMNA#20 pinout, R5F121BAMNA#20 application, or R5F121BAMNA#20 equivalent, this page delivers verified technical context, validated pin functions, application-specific design value, and confirmed alternative options for industrial control, sensor interface, and HMI subsystem designs requiring extended temperature operation and integrated touch capability.

Technical Context

The R5F121BAMNA#20 implements the RL78 CPU core with CISC architecture and 3-stage pipeline, supporting configurable instruction execution time from 0.0625 μs (@16 MHz high-speed on-chip oscillator) to 30.5 μs (@32.768 kHz subsystem clock). It integrates dedicated hardware blocks including a 99-year RTC with alarm and correction, background operation–independent data flash (1 KB, 1M rewrite cycles), and a 15-channel capacitive touch sensing unit (CTSU) supporting both self- and mutual-capacitance configurations.

Its peripheral set includes three serial interfaces (UART, simplified SPI/CSI, simplified I²C), one full I²C channel, 16-bit timer array with 8 channels plus 12-bit interval timer and watchdog, and analog resources comprising 11-channel 10-bit A/D converter with internal reference (0.815 V), two comparators, and on-chip temperature sensor - all operating within the same 2.4–5.5 V supply and −40°C to +125°C ambient range.

Key Specifications

Pinout & Package

Package: HWQFN-32 (5.0 × 5.0 mm, 0.5-mm pitch), thermally enhanced with exposed die pad requiring non-electrical PCB soldering per Renesas specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with R5F121BCMNA#20 (identical silicon) and R5F121BCGNA#20 (G-grade thermal variant), the R5F121BAMNA#20 delivers full M-grade qualification for extreme-temperature deployments while maintaining pin-to-pin compatibility and identical peripheral functionality - making it the definitive choice for under-hood or high-heat industrial applications.

Availability

R5F121BAMNA#20 is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, appliance touch interfaces, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for R5F121BAMNA#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 Corporation is a global semiconductor leader specializing in microcontrollers, analog, and power solutions for automotive, industrial, and IoT markets.

The RL78/G16 group targets cost-sensitive, low-power embedded systems requiring integrated analog, timing, and human-machine interface features - designed specifically for industrial controls, appliances, and sensor edge nodes where reliability and thermal robustness are critical.

FAQ

What is the maximum operating frequency and voltage range supported by the R5F121BAMNA#20?

The R5F121BAMNA#20 operates at up to 16 MHz using its high-speed on-chip oscillator, with supply voltage ranging from 2.4 V to 5.5 V. Its frequency accuracy is ±1.5% over the full −40°C to +125°C industrial temperature range, and it supports ultra-low-speed operation down to 32.768 kHz for RTC and low-power modes - all within the same VDD window. This eliminates need for external clock sources across most applications.

Does the R5F121BAMNA#20 include an integrated real-time clock with calendar function?

Yes, the R5F121BAMNA#20 integrates a full-featured real-time clock (RTC2) with 99-year calendar, alarm generation, and clock correction capability. It operates independently using the 32.768 kHz subsystem clock and retains timekeeping during STOP mode. The RTC2 block requires no external components and is fully accessible via on-chip registers - a key differentiator versus basic timer-based RTC implementations.

How many analog input channels and what A/D resolution does the R5F121BAMNA#20 provide?

The R5F121BAMNA#20 provides 11 analog input channels with 10-bit A/D conversion resolution. It includes an internal reference voltage of 0.815 V (typical), selectable temperature sensor, and touch-sensing voltage (TSCAP) input - all usable simultaneously. The A/D converter supports single- and continuous-conversion modes with programmable sampling time, enabling precise sensor measurements without external signal conditioning.

What is the purpose and capability of the CTSU in the R5F121BAMNA#20?

The Capacitive Touch Sensing Unit (CTSU) in the R5F121BAMNA#20 supports 15 independent touch channels using either self-capacitance (15 keys) or mutual-capacitance (up to 16 keys in matrix) methods. It includes hardware-based noise cancellation, automatic drift compensation, and programmable sensitivity - enabling robust touch operation in noisy industrial environments without host CPU intervention.

Is the R5F121BAMNA#20 pin-compatible with other RL78/G16 variants in the same package?

Yes, the R5F121BAMNA#20 is fully pin-compatible with all other RL78/G16 devices in the HWQFN-32 package, including R5F121BCMNA#20 and R5F121BCGNA#20. Pin functions, electrical characteristics, and mechanical footprint are identical; only temperature grade (M vs. G) and ordering code differ - enabling drop-in replacement and design reuse across qualification tiers.