MC9RS08KB8CWJ - 8-Bit 20MHz RS08 MCU | NXP Semiconductors
MPN: MC9RS08KB8CWJ ✓ Active| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
MC9RS08KB8CWJ Overview
What is an RS08 microcontroller? An RS08 MCU is an 8-bit embedded microcontroller, a member of the broader microcontroller and semiconductor hierarchy. It combines a compact central processing unit with on-chip program memory, interrupt capability, and integrated peripherals. The RS08KB family is positioned for small control systems where low component count, deterministic control, and simple firmware execution are useful. Its 20 MHz CPU provides a higher operating speed than basic 8-bit devices while retaining the simplicity of the RS08 instruction set.
Key verified features include an 8-bit CPU, operation up to 20 MHz, 8 KB Flash memory, 8K x 8 organization, a 20-pin SOIC package, and a stated 5.5 V maximum supply condition across the temperature range. The family description also identifies support for interrupt capability and compatibility with other 5 V families. These attributes make the MC9RS08KB8CWJ suitable for compact appliance controls, sensor-conditioning systems, simple motor-control functions, and low-cost embedded products.
The MCU’s 8 KB Flash capacity is appropriate for moderate control firmware, while the 8-bit architecture simplifies resource budgeting and peripheral integration. The supplied sources identify the lifecycle as ACTIVE on one technical datasheet page, although the NXP product page contains an End of Life overview. Because lifecycle and procurement conditions can change, purchasing decisions should confirm current NXP or authorized-distributor status for the exact orderable MPN.
When designing a board around the MC9RS08KB8CWJ, use the 20-pin SOIC footprint and verify every signal against the applicable datasheet pinout before layout. The device is intended for 5 V-oriented embedded systems; input levels, peripherals, clocking, programming, and decoupling must be designed around the verified electrical limits rather than inferred from generic 8-bit MCU conventions.
This page consolidates the verified RS08KB specifications, sourcing links, lifecycle evidence, and engineering-oriented design cautions. It distinguishes known facts such as CPU speed, Flash size, package, and voltage information from unavailable details rather than estimating electrical values or package pin assignments.
Drop-in alternatives for MC9RS08KB8CWJ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MC9RS08KB8CWJ (same form factor and footprint) — differing in Package, Program Memory Size, Instruction Set, Peripherals, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9RS08KA8CWJ
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View Datasheet →MC9RS08KA4CWJ
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View Datasheet →MC9RS08KA2CDB
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View Datasheet →MC9RS08KB8CTG
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View Datasheet →MC9RS08KB12CSG574
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View Datasheet →MC9RS08KB8CWJ Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit microcontroller |
| CPU Core | RS08 |
| CPU Architecture | 8-bit |
| Maximum CPU Frequency | 20 MHz |
| Program Memory | 8 KB Flash |
| Flash Organization | 8K x 8 |
| Supply Voltage | 2.5 V / 3.3 V / 5 V |
| Maximum Stated Voltage | 5.5 V across temperature range |
| Package | 20-pin SOIC |
| Package Family | SOIC |
| Mounting Type | Surface Mount |
| Instruction Set | Subset of HC08 instruction set with added BGND instruction |
| Interrupt Architecture | Single Global interrupt vector |
| Core Feature | Interrupt capability |
| Life Cycle Stage | ACTIVE |
| Legacy Manufacturer | Freescale Semiconductor |
| Supplier Context | NXP Semiconductors |
MC9RS08KB8CWJ soic Pin Configuration Guide
Pin configuration for MC9RS08KB8CWJ (soic 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 MC9RS08KB8CWJ.
Refer to the datasheet for full pin configuration.
Typical Applications
MC9RS08KB8CWJ is suitable for 6 applications: Compact Appliance Control, Sensor Interface Module, Simple Motor Sequencing Control, Low-Cost Consumer Device, Industrial Sequence Controller, Programmable Control Node.
Compact Appliance Control
The MC9RS08KB8CWJ fits compact appliance-control boards that need an 8-bit MCU, a 20 MHz CPU, and 8 KB of Flash without a larger memory footprint. Its RS08KB-family interrupt capability can support time-sensitive control tasks such as button handling, sensor updates, and actuator sequencing. The verified 20-pin SOIC package helps preserve a conventional surface-mount layout, while the stated 5 V, 3.3 V, and 2.5 V supply options support multiple board architectures. Before final release, verify the exact I/O limits, timer resources, and programming signals from the manufacturer datasheet.
Recommended
Sensor Interface Module
MC9RS08KB8CWJ can serve as the controller in a small sensor-interface module where the required firmware fits within 8 KB of Flash and the design needs deterministic interrupt handling. The 20 MHz CPU provides headroom for sampling, filtering, threshold evaluation, and status reporting, while the single global interrupt vector identifies a compact interrupt architecture for embedded control. The verified data does not specify individual sensor peripherals, so the module’s ADC, serial interface, and I/O requirements must be checked against the exact datasheet before component commitment.
Recommended
Simple Motor Sequencing Control
The MC9RS08KB8CWJ is suitable for simple motor sequencing or actuator-control subsystems when the controller must coordinate discrete steps, monitor inputs, and respond to interrupts. Its 8-bit architecture simplifies firmware for basic state machines, and the 20 MHz CPU offers more execution headroom than a low-clock general-purpose 8-bit device. The verified information does not identify motor-driver outputs, PWM channels, or current ratings, so this application requires an external driver and a complete peripheral check. Use the exact package pinout and electrical limits before routing control signals.
Recommended
Low-Cost Consumer Device
MC9RS08KB8CWJ can support a low-cost consumer device that needs modest firmware, basic digital I/O, and compact board area. The 8 KB Flash allocation is appropriate for a focused product rather than a connectivity-heavy application, and the 20-pin SOIC package is convenient for automated assembly. The verified source identifies 5 V, 3.3 V, and 2.5 V options, allowing the MCU to be evaluated in different rail arrangements. Compliance status, ESD rating, brownout behavior, and exact I/O tolerances are not available in the supplied data and must be verified before production.
Recommended
Industrial Sequence Controller
The MC9RS08KB8CWJ may be used in a small industrial sequence controller where interrupt-driven inputs, compact firmware, and a 5 V-oriented control environment are priorities. The 20 MHz RS08 CPU can execute a state machine for discrete process steps, while the 8 KB Flash limits firmware size and encourages a focused control architecture. Because the verified data does not specify industrial qualification, isolation, extended-temperature performance, or protected I/O levels, this application should use appropriate interface protection and require confirmation of the exact environmental ratings.
Recommended
Programmable Control Node
MC9RS08KB8CWJ can act as a programmable control node for a small distributed system that gathers local inputs, executes embedded logic, and reports status. The interrupt capability described for the RS08KB family is useful for event-driven nodes, while 20 MHz execution supports protocol handling and control logic when firmware remains within the available 8 KB Flash. The verified sources do not identify a specific communication peripheral or programming interface, so the node’s UART, SPI, I2C, or other communications requirements must be checked against the exact device documentation.
Recommended
Recommended Products Summary
Engineering reference data for MC9RS08KB8CWJ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9RS08KA8CWJ | MC9RS08KA4CWJ | MC9RS08KA2CDB | MC9RS08KB8CTG | MC9RS08KB12CSG574 |
|---|---|---|---|---|---|---|
| Product Type | 8-bit RS08 microcontroller | RS08-family comparison candidate | RS08-family microcontroller | RS08-family microcontroller | RS08-family MCU | RS08-family MCU |
| Package | 20-pin SOIC | 20-pin SOIC - verification required | 20-pin SOIC - verification required | 20-pin SOIC - verification required | 20-pin SOIC - verification required | 20-pin SOIC - verification required |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
Key Differentiators
- Verified RS08KB-family identity with 8-bit CPU and 8 KB Flash (vs MC9RS08KA8CWJ)
- 20 MHz operating speed (vs MC9RS08KA4CWJ)
- 20-pin SOIC footprint (vs MC9RS08KB8CTG)
- Documented supply-option positioning (vs MC9RS08KB12CSG574)
Design Notes
Treat the 20-pin SOIC footprint as the starting point, but do not route the board until the exact MC9RS08KB8CWJ pinout is obtained from the manufacturer datasheet. Confirm pin 1 orientation, exposed programming signals, ground locations, and alternate-function assignments before placing traces. The verified data identifies the package but does not provide a complete pin table.
The verified sources identify 2.5 V, 3.3 V, and 5 V supply options and state 5.5 V across the temperature range. Do not interpret 5.5 V as a design target or universal operating limit; verify the exact operating and absolute-maximum ratings for every supply and I/O pin. Place the datasheet-recommended bypass capacitors near the appropriate supply pins and confirm regulator tolerance, startup behavior, and decoupling with the final load.
MC9RS08KB8CWJ and other RS08-family parts may differ in memory size, peripheral availability, interrupt details, and package pin functions even when their names or package families are similar. MC9RS08KA8CWJ appears in the cross-reference results, but that does not prove pin compatibility. Review the exact MPN datasheet, programming requirements, and board-level pin mapping before approving a replacement.
For an interrupt-driven embedded controller, keep the MCU power path short and follow the manufacturer’s recommended decoupling arrangement. Leave adequate clearance around programming and debug access, and route sensitive input paths away from sources of switching noise. Because the verified data does not specify analog features, oscillator connections, or communication peripherals, do not infer those connections from the 8-bit architecture.
Compliance Information
The supplied verified search results do not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status for MC9RS08KB8CWJ. Compliance must be confirmed from the exact manufacturer datasheet or current supplier documentation.