MC9RS08KB4CWJ - 8-bit RS08 MCU, 4KB Flash, 20MHz | NXP
Référence : MC9RS08KB4CWJ ✗ Fin de vie| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $2.85 | $2,85 |
| 10 | $2.55 | $25,50 |
| 100 | $2.18 | $218,00 |
| 500 | $1.74 | $870,00 |
| 1 000 | $1.49 | $1 490,00 |
MC9RS08KB4CWJ Présentation
A microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (ROM/Flash), working memory (RAM), and peripherals such as timers, communication ports, and analog blocks. The MC9RS08KB4CWJ belongs to the taxonomy: microcontroller -> 8-bit MCU -> RS08 core MCU -> RS08KB family -> low-cost general-purpose embedded controller. The RS08KB line sits at the entry level of NXP's 8-bit portfolio and is designed for fans, white goods, motor control, simple sensor readouts, and human-machine interface (HMI) edge nodes where 32-bit MCUs would be over-spec and unnecessarily expensive.
Key features include 18 general-purpose I/O pins, a 16-bit timer/PWM module, an 8-bit analog-to-digital converter (ADC) on most family members, on-chip debug via background debug mode (BDM), and integrated peripherals including a real-time counter (RTC), watchdog timer (WDT), low-voltage detect (LVD), and power-on reset (POR). The device supports I2C and SPI connectivity for sensor and external peripheral interfacing, reducing external component count. The wide 2.5 V to 5.5 V operating range allows direct connection to 5 V rails or 2x AA / 3x AA battery stacks.
Architecturally, the RS08 core implements a subset of the HC08 instruction set, retaining byte-efficient BCD and bit-manipulation operations favored in legacy 8-bit code while shrinking die area. The 20 MHz internal bus and 4 KB Flash enable small real-time control loops, while the 126 B SRAM is sufficient for modest state machines and protocol stacks (e.g., simple proprietary RF, sensor fusion at low sample rates).
Typical applications include small appliance control (rice cookers, fans, blenders), LED drivers, battery chargers, low-cost remote controls, sensor interfaces, and 5 V industrial sensor conditioning. The on-chip peripherals (ADC, PWM, timers, I2C/SPI) enable single-chip solutions in space-constrained designs, eliminating external driver or decoder ICs.
When designing with the MC9RS08KB4CWJ, place a 100 nF decoupling capacitor as close as possible to the VDD pin and a 10 uF bulk capacitor on the board supply. Keep the BDM debug header accessible during prototype bring-up - the RS08KB requires the BDM interface for programming and in-circuit debugging.
This page synthesizes distributor pricing, drop-in alternatives within the RS08 family, and practical design notes not found in the manufacturer datasheet alone.
Alternatives de remplacement direct pour MC9RS08KB4CWJ — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec MC9RS08KB4CWJ (même facteur de forme et même empreinte) — différant par Package, Program Memory Size, Instruction Set, Peripherals, Mounting Type.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
MC9RS08KB8CWJ
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
Contactez-nous pour le prix
Voir la fiche technique →MC9RS08KB2CWJ
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
MC9RS08KA8CWJ
✅ Remplacement direct✓ En stock
$1.68 / unité
Voir la fiche technique →MC9RS08KA4CWJ
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$1.02 / unité
Voir la fiche technique →MC9RS08KA2CWJ
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
MC9RS08KB4CSC
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MC9RS08KB4CWJ Valeurs maximales et caractéristiques électriques
| Core Processor | RS08 |
| Core Size | 8-bit |
| CPU Speed | 20 MHz |
| Program Memory Size | 4 KB (4K x 8) Flash |
| RAM Size | 126 B |
| EEPROM Size | None (Flash-based) |
| Number of I/O | 18 |
| Supply Voltage Range | 2.5 V to 5.5 V |
| Connectivity | I2C, SPI |
| Peripherals | LVD, POR, PWM, WDT |
| Instruction Set | HC08 subset + BGND |
| Boîtier | 20-pin SOIC (wide-body, tube) |
| Type de montage | Surface Mount |
| Température de fonctionnement | -40C to +85C |
| Debug Interface | Background Debug Mode (BDM) |
| Largeur du bus de données | 8-bit |
Configuration des broches de MC9RS08KB4CWJ
| Broche 1 | PTA0/KBIP0 — GPIO port A bit 0 / keyboard interrupt pin 0 |
| Broche 2 | PTA1/KBIP1 — GPIO port A bit 1 / keyboard interrupt pin 1 |
| Broche 3 | PTA2/KBIP2 — GPIO port A bit 2 / keyboard interrupt pin 2 |
| Broche 4 | PTA3/KBIP3 — GPIO port A bit 3 / keyboard interrupt pin 3 |
| Broche 5 | VDD — Supply voltage (2.5 V to 5.5 V) |
| Broche 6 | VSS — Ground reference |
| Broche 7 | PTA4/TCLK — GPIO port A bit 4 / timer clock input |
| Broche 8 | PTA5/RESET — GPIO port A bit 5 / reset input (bidirectional) |
| Broche 9 | PTB0/SDA — GPIO port B bit 0 / I2C SDA |
| Broche 10 | PTB1/SCL — GPIO port B bit 1 / I2C SCL |
| Broche 11 | PTB2/MOSI — GPIO port B bit 2 / SPI MOSI |
| Broche 12 | PTB3/MISO — GPIO port B bit 3 / SPI MISO |
| Broche 13 | PTB4/SPSCK — GPIO port B bit 4 / SPI clock |
| Broche 14 | PTB5/SS — GPIO port B bit 5 / SPI slave select |
| Broche 15 | PTB6 — GPIO port B bit 6 |
| Broche 16 | PTB7 — GPIO port B bit 7 |
| Broche 17 | PTC0/TPMCH0 — GPIO port C bit 0 / TPM channel 0 (PWM) |
| Broche 18 | PTC1/TPMCH1 — GPIO port C bit 1 / TPM channel 1 (PWM) |
| Broche 19 | BKGD/MS — Background Debug Mode / Mode Select |
| Broche 20 | PTC2 — GPIO port C bit 2 |
Applications typiques
MC9RS08KB4CWJ convient pour 8 applications: Small Appliance Control, Battery-Powered Remote Controls, LED Lighting Drivers, Industrial Sensor Interfaces, Low-Cost Battery Chargers, Fan and Motor Control (BLDC Drivers), HMI Keypanels and Simple Displays, Toys and Educational Electronics.
Small Appliance Control
The MC9RS08KB4CWJ's 4 KB Flash, 18 GPIO, and integrated PWM module fit small household appliances such as rice cookers, blenders, fans, and kettles that need precise temperature or motor control. With the RS08 core executing at 20 MHz, control-loop latency stays under 50 us for typical 1 kHz PID cycles used in heating elements. The 2.5-5.5 V operating range matches standard mains-rectified supplies after regulation, eliminating level shifters. On-chip BDM allows in-circuit firmware updates during production calibration, cutting manufacturing test time. Compared with discrete logic controllers, the MCU reduces BoM by integrating ADC input, PWM output, and timer-based scheduling in one SOIC-20 footprint.
Recommandé
Battery-Powered Remote Controls
For handheld IR/RF remote controls and small wireless sensor nodes, the MC9RS08KB4CWJ offers a compact 20-pin SOIC, 126 B SRAM, and 2.5 V minimum operation directly supporting 2x AA alkaline batteries. The RS08KB family's wait and stop modes enable sub-10 uA quiescent current, extending battery life well past 6 months in typical remote-control duty cycles. The integrated I2C/SPI interfaces let engineers add accelerometers or temperature sensors without external glue logic, while the 4 KB Flash fits modest proprietary protocol stacks. Compared with discrete encoder ICs, this MCU replaces both the encoder chip and several support passives.
Recommandé
LED Lighting Drivers
The MC9RS08KB4CWJ suits LED driver and dimmer applications because its PWM module provides smooth dimming via duty-cycle control at audio-band-switching frequencies that avoid flicker. The 18 GPIO lines can drive multiple LED strings through external MOSFETs, while the 8-bit ADC reads ambient light sensors for closed-loop brightness control. Operating at 2.5-5.5 V supports both 5 V USB-LED strips and 3.3 V smart-bulb supplies. The 20 MHz RS08 core handles PWM fades, color-mixing math, and simple wireless-protocol stacks in a single IC. Compared with analog LED drivers, the MCU adds programmability without compromising dimming smoothness.
Recommandé
Industrial Sensor Interfaces
For 5 V industrial sensor-conditioning boards, the MC9RS08KB4CWJ provides 18 GPIO for digital I/O, an 8-bit ADC for analog sensor reading, and I2C/SPI for digital sensor expansion. The RS08 core performs linearization, calibration, and Modbus-like protocol framing at 20 MHz, sufficient for typical 100 Hz sensor sampling rates. Wide 2.5-5.5 V operation tolerates regulated 24 V industrial rails stepped down by simple linear or buck regulators. On-chip LVD and POR increase robustness in noisy factory environments. Compared with analog signal conditioners, this MCU adds configurability and digital diagnostics with the same BoM cost.
Recommandé
Low-Cost Battery Chargers
The MC9RS08KB4CWJ fits single-cell Li-ion / NiMH chargers that need CC/CV profile control with safety timers and temperature monitoring. The PWM module drives the switching converter at user-defined frequency, while the ADC measures battery voltage, current, and thermistor inputs in real time. The 4 KB Flash stores charging profile parameters, fault recovery routines, and LED status indicators. Its 2.5-5.5 V range accepts USB 5 V supplies directly, simplifying travel-charger designs. Compared with dedicated charger ICs, the MCU adds customization for proprietary battery chemistries without sacrificing cost.
Recommandé
Fan and Motor Control (BLDC Drivers)
The MC9RS08KB4CWJ's combination of PWM outputs, 20 MHz CPU, and 18 GPIO suits small BLDC and brushed-DC fan controllers used in HVAC, computer cooling, and appliance ventilation. The RS08KB's timer architecture supports complementary PWM with dead-time insertion for H-bridge drive, while the integrated ADC samples back-EMF for sensorless commutation algorithms. Operating from 5 V rails, the MCU interfaces directly to 5 V gate drivers without level translation. The 4 KB Flash handles sensorless trapezoidal commutation code plus UART diagnostics. Compared with dedicated motor-controller ICs, this MCU allows field tuning of RPM curves and soft-start profiles.
Recommandé
HMI Keypanels and Simple Displays
The MC9RS08KB4CWJ drives keypanel matrices and small status-LED HMI panels used in industrial equipment, vending machines, and audio devices. With 18 GPIO, the MCU scans up to a 3x5 key matrix while driving LED status indicators through PWM dimming. I2C expansion ports allow connection of character LCD or OLED displays without additional drivers. RS08 core delivers responsive button debounce at sub-5 ms without taxing the 4 KB Flash budget. Compared with dedicated key-scan ICs, the MCU adds flexible mapping and LED-animation routines in a single chip, simplifying BoM and PCB layout.
Recommandé
Toys and Educational Electronics
The MC9RS08KB4CWJ's low-cost 8-bit performance, 4 KB Flash, and integrated PWM make it a strong fit for hobbyist electronics, educational kits, and consumer toys. The BDM debug interface lets students program in-circuit, while the 20 MHz RS08 core teaches introductory embedded concepts without overwhelming complexity. The SOIC-20 wide-body package handles hand-soldering for prototypes and educational labs. I2C/SPI connectivity enables sensor add-on modules for STEM projects. Compared with lower-end 4-bit microcontrollers, this MCU offers modern C-programmability at comparable BoM cost.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour MC9RS08KB4CWJ — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | MC9RS08KB8CWJ | MC9RS08KB2CWJ | MC9RS08KA8CWJ | MC9RS08KA4CWJ | MC9RS08KB4CSC |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 20-pin SOIC (wide-body) | 20-pin SOIC (wide-body) - same | 20-pin SOIC (wide-body) - same | 20-pin SOIC (wide-body) - same | 20-pin SOIC (wide-body) - same | 20-pin SOIC (wide-body) - same |
| Core | RS08 8-bit | RS08 8-bit - same | RS08 8-bit - same | RS08 8-bit - same | RS08 8-bit - same | RS08 8-bit - same |
| CPU Speed | 20 MHz | 20 MHz - same | 20 MHz - same | 20 MHz - same | 20 MHz - same | 20 MHz - same |
| Flash Size | 4 KB | 8 KB (+100%) | 2 KB (-50%) | 8 KB (+100%) | 4 KB (same) | 4 KB (same) |
| RAM Size | 126 B | 126 B - same | 126 B - same | 126 B - same | 126 B - same | 126 B - same |
| I/O Pins | 18 | 18 - same | 18 - same | 18 - same | 18 - same | 18 - same |
| Supply Voltage | 2.5 V to 5.5 V | 2.5 V to 5.5 V - same | 2.5 V to 5.5 V - same | 2.5 V to 5.5 V - same | 2.5 V to 5.5 V - same | 2.5 V to 5.5 V - same |
| Connectivity | I2C, SPI | I2C, SPI - same | I2C, SPI - same | I2C, SPI - same | I2C, SPI - same | I2C, SPI - same |
| Debug Interface | BDM | BDM - same | BDM - same | BDM - same | BDM - same | BDM - same |
Principaux différenciateurs
- Largest drop-in Flash upgrade within the same RS08KB family (vs MC9RS08KB2CWJ)
- KA family baseline offering same Flash size (vs MC9RS08KA4CWJ)
- Tube packaging for prototype-friendly handling (vs MC9RS08KB4CSC)
- Wide 5 V supply tolerance out of the box (vs Modern 3.3 V-only Cortex-M0+ MCUs)
Notes de conception
Place a 100 nF ceramic decoupling capacitor within 5 mm of the VDD pin (pin 5) and a 10 uF bulk capacitor on the supply rail. The RS08KB integrates a low-voltage detect (LVD) module; configure it via the SPMSC1 register with the desired trip voltage to enable safe reset behavior on brown-out conditions. For battery applications using 2 x AA cells, verify hold-up time of the bulk capacitor at peak load current (~10 mA GPIO drive) is sufficient to ride out brief supply dips.
Route the BKGD/MS pin (pin 19) directly to a programming header with no series resistance above 100 ohm; the BDM interface uses edge-sensitive signaling that is degraded by long stubs. Keep the RESET line (pin 8) short with a 10 kohm pull-up to VDD and a 100 nF decoupling cap if used in noisy environments. Wide-body SOIC-20 footprint provides ample clearance for hand-soldering during prototypes and rework during production engineering changes.
Do not exceed 5.5 V on VDD - the RS08KB core is not 5 V tolerant on I/O when supply is below 3 V, so verify absolute maximum ratings before interfacing to external 5 V peripherals. The BDM and reset pins share PTA5/RESET and BKGD/MS dual functions; lock the appropriate pin function via configuration registers before enabling them as GPIO to avoid spurious resets during firmware startup. The internal 4 KB Flash has limited endurance (~10k write cycles typical) - avoid using Flash for non-volatile data storage without wear-leveling strategy.
At 20 MHz CPU speed with all peripherals active, the RS08KB typically draws 6-8 mA from VDD. With a SOIC-20 wide-body thermal resistance of approximately 85 C/W, the junction temperature rise is well below 1 C above ambient, so no heatsinking is required. For applications operating above +85 C ambient, derate clock speed or reduce peripheral clock gating to keep junction below +125 C maximum. No external thermal management is required for the typical industrial temperature range.
Informations de conformité
Compliance data not present in the verified web sources for this part. Per the NXP RS08KB family product page, the part is approaching end-of-life status. Confirm RoHS/REACH compliance with NXP directly via the part's environmental quality document before placing production orders.
