R5F21237JFP - 16-Bit 20MHz MCU 48KB Flash | Renesas
MPN: R5F21237JFP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
R5F21237JFP Overview
A microcontroller is a programmable semiconductor that integrates a CPU, memory, and peripherals on one device. The R8C/23 belongs to the Renesas MCU family within the broader embedded-controller hierarchy, where a general-purpose CPU core executes firmware while timers, serial interfaces, analog functions, and digital I/O interact with external hardware.
The verified product information identifies a 48 KB (48K x 8) flash memory organization and a maximum clock frequency of 20 MHz. Renesas describes the silicon-gate CMOS implementation as providing a high level of instruction efficiency. These characteristics make the MCU suitable for compact embedded controllers whose firmware must coordinate several peripheral functions while operating from a 3 V or 5 V system supply.
The R5F21237JFP is packaged in a 48-pin plastic molded LQFP measuring 7 x 7 mm. This surface-mount format supports conventional PCB assembly while exposing more I/O than smaller microcontroller packages. Exact peripheral inventories, RAM organization, timer resources, analog performance, and individual pin assignments are not stated in the supplied source material and should be confirmed in the manufacturer datasheet before schematic capture.
Typical design uses include industrial control modules, sensor conditioning, communication equipment, motor or actuator control, and compact consumer appliances. Designers should validate the required peripherals, interrupt vectors, timing performance, and pin multiplexing against the Renesas R8C/23 documentation before committing the PCB layout.
The main implementation consideration is firmware and timing compatibility during any lifecycle transition. Because the R8C/23 is supported only for customers already using the family, engineers should confirm availability, current lifecycle status, toolchain support, and any approved alternate source before a new production release.
This page combines verified distributor and Renesas product information with package, application, comparison, and sourcing guidance. It identifies where the R5F21237JFP fits while separating documented facts from details that require manufacturer confirmation.
Drop-in alternatives for R5F21237JFP — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
R5F21238JFP
✅ Drop-In📋 Reference alternative (not in catalog)
R5F21237JFP-W4
✅ Drop-In📋 Reference alternative (not in catalog)
R5F21237JFP#U1
✅ Drop-In📋 Reference alternative (not in catalog)
R5F21237JFP Maximum Ratings & Electrical Characteristics
| Product Type | 16-bit microcontroller (MCU) |
| Product Series | R8C/23 Group |
| CPU Core | R8C CPU core |
| Maximum CPU Frequency | 20 MHz |
| Flash Memory | 48 KB (48K x 8) |
| Additional Memory | 2 KB |
| Address Space | 1 Mb |
| Operating Supply | 3/5 V |
| Process Technology | High-performance silicon gate CMOS |
| Instruction Set | 16-bit CISC |
| Package | 48-pin plastic molded LQFP (7 x 7 mm) |
| Mounting Type | Surface mount |
| Pin Count | 48 pins |
| Operating Temperature | -40°C to +85°C |
| Lead-Free Status | Pb-free |
| RoHS Status | unknown |
| REACH Status | unknown |
| AEC-Q100 Status | not_applicable |
R5F21237JFP 48-pin plastic molded lqfp (7 x 7 mm) Pin Configuration Guide
Pin configuration for R5F21237JFP (48-pin plastic molded lqfp (7 x 7 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for R5F21237JFP.
Refer to the datasheet for full pin configuration.
Typical Applications
R5F21237JFP is suitable for 6 applications: Industrial Embedded Control, Sensor Conditioning and Data Acquisition, Communication Interface Module, Actuator and Motor Sequencing, Consumer Appliance Controller, Legacy Equipment Maintenance.
Industrial Embedded Control
The Renesas R5F21237JFP fits compact industrial controllers that coordinate sensors, digital I/O, and timed control functions within a 3/5 V system. Its 20 MHz maximum clock provides a defined performance ceiling for the R8C CPU core, while 48 KB of flash stores application firmware without requiring an external memory device. The 48-pin LQFP gives an implementation more routing options than a small leadless package. Before schematic capture, confirm the exact timers, serial channels, ADC resources, and interrupt assignments required by the controller because these details are not present in the supplied search excerpts.
Recommended
Sensor Conditioning and Data Acquisition
The R5F21237JFP can serve as the supervisory MCU in a sensor-conditioning module where firmware must sample external sensors, apply control logic, and present processed results. Its 16-bit R8C CPU core and 48 KB program flash are suited to self-contained embedded firmware, and the 3/5 V operating arrangement supports common industrial logic rails. The 48-pin package provides substantial I/O capacity for sensors, indicators, and communications. Verify analog-channel availability, ADC resolution, sampling behavior, and calibration requirements in the Renesas datasheet before assigning precision measurement functions to this MCU.
Recommended
Communication Interface Module
The R5F21237JFP is suitable for a communication terminal that manages serial framing, local control, status reporting, and protocol conversion. Its 20 MHz maximum operating frequency and 48 KB flash provide resources for embedded protocol stacks, while the 48-pin LQFP exposes enough pins for multiple interfaces and discrete status indicators. In a networked design, the MCU can coordinate an Ethernet PHY such as the KSZ8001LI, provided the required UART or parallel host interface is available. Confirm pin multiplexing, interrupt priorities, and timing margins in the official R8C/23 documentation.
Recommended
Actuator and Motor Sequencing
The R5F21237JFP can manage actuator sequencing in equipment requiring deterministic timed outputs and supervisory logic. The 20 MHz R8C CPU core can execute control tasks, while 48 KB flash accommodates state-machine and safety-sequencing firmware. The 3/5 V supply arrangement simplifies integration with logic-level drivers, and the 48-pin LQFP provides enough connections for pulse inputs, limit sensors, and driver-enable signals. Because the supplied data does not detail PWM channels, timer counts, or motor-control peripherals, engineers must verify those resources and the required output timing directly from the manufacturer datasheet.
Recommended
Consumer Appliance Controller
The R5F21237JFP is appropriate for appliance controllers that combine user inputs, display or indicator control, and a small embedded state machine. Its 48 KB flash supports a self-contained firmware image, and the 16-bit architecture provides more arithmetic headroom than an 8-bit controller for motor, timing, or signal-processing tasks. The package's 48 pins allow several discrete controls to remain on one PCB. Its documented -40°C to +85°C range can suit many ambient environments, but lifecycle constraints, toolchain availability, and the exact peripheral set should be reviewed for appliance production volumes.
Recommended
Legacy Equipment Maintenance
The R5F21237JFP is especially relevant to maintenance and continuation programs for equipment already built around the R8C/23 family. The official Renesas notice says the group is supported for customers that have already adopted these products, which makes it useful for preserving proven firmware and board continuity. Its 20 MHz clock, 48 KB flash, and 48-pin LQFP reproduce the established device characteristics. For obsolete or unavailable stock, the verified R5F21238JFP migration path offers the same reported I/O count and peripheral set, but firmware capacity and register-level behavior must be reviewed before substitution.
Recommended
Recommended Products Summary
Engineering reference data for R5F21237JFP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | R5F21238JFP | R5F21237JFP-W4 | R5F21237JFP#U1 |
|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Package | LQFP-48 (7x7 mm) | LQFP-48 (7x7 mm) | LQFP-48 (7x7 mm) | LQFP-48 (7x7 mm) |
| CPU Core | R8C CPU core | R8C/23 family | R8C CPU core | R8C CPU core |
| Flash Memory | 48 KB | 64 KB | 48 KB | 48 KB |
Key Differentiators
- Preserves the established R8C/23 memory and peripheral platform (vs R5F21238JFP)
- Matches the exact base device across available ordering suffixes (vs R5F21237JFP#U1)
- Uses the same 48-pin 7 x 7 mm LQFP package (vs R5F21237JFP-W4)
Design Notes
Design the 3/5 V supply rail around the exact operating-mode limits and I/O thresholds listed in the Renesas datasheet; the supplied search excerpts establish a 3/5 V operating arrangement but do not provide minimum and maximum rail voltages. Check brownout behavior, input leakage, and peripheral load current during wake and active states. Place local bulk and bypass capacitance at the MCU supply pins according to the manufacturer's reference layout rather than relying on a generic capacitor rule.
Use a 48-pin LQFP land pattern and route all 48 terminals to the programmed device before committing a new PCB. Keep switching nodes, high-current loads, and sensitive analog inputs away from MCU pins and supply-return paths. Verify the exposed thermal behavior, assembly profile, and package tolerances from the manufacturer package drawing. A valid schematic based only on the 7 x 7 mm package name is insufficient because ball-out and alternate-function details remain necessary.
Do not assume that a 64 KB-flash alternative is firmware-compatible merely because the I/O count and peripheral set match. The verified R5F21238JFP candidate adds 16 KB of flash, and changes in interrupt vectors, startup code, or memory mapping may require code review. Preserve the original R8C toolchain, linker configuration, startup routine, and device programming files, then perform boundary, timing, and brownout tests before approving the migration.
Because Renesas states that the R8C/23 group is supported only for customers already using it, avoid introducing the R5F21237JFP into a fresh platform without formal supplier approval. Obtain written lifecycle, PCN, and allocation information for the exact ordering code. If the family is unsuitable for new adoption, migrate to a currently supported MCU and treat that as a deliberate redesign rather than a pin-compatible substitute.
Compliance Information
The verified Mouser listing identifies R5F21237JFP#U1 as Pb-free. No explicit RoHS, REACH, halogen-free, or conflict-minerals declaration was supplied, so those values remain unknown.
