MC9RS08KA8CWG - 8-bit RS08 MCU, 8KB Flash, 20MHz | NXP
MPN: MC9RS08KA8CWG ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.75 | $2.75 |
| 10 | $2.45 | $24.50 |
| 100 | $2.1 | $210.00 |
| 500 | $1.78 | $890.00 |
| 1,000 | $1.52 | $1,520.00 |
MC9RS08KA8CWG Overview
RS08 microcontrollers belong to the broader 8-bit MCU family and are derived from the legacy HC08 architecture via the simplified RS (Reduced State) core. The RS08KA family sits within the Freescale/NXP 8-bit portfolio, between simple 4/8-pin devices and the more feature-rich S08 family. Within the system hierarchy, an 8-bit MCU such as this sits at the sensing, control, and glue-logic layer of an embedded design - below 32-bit application processors and above purely analog components. The RS08 core drops some HC08 instructions and addressing modes in exchange for smaller die area and lower cost, while retaining a usable interrupt controller and peripheral set.
Key features of the MC9RS08KA8CWG include 8KB Flash program memory, 20 MHz bus/Core clock (from an internal source with optional trimming), on-chip voltage regulator for wide 2.5 V to 5.5 V supply operation, multiple low-power stop modes, an integrated Analog-to-Digital Converter (ADC), timers, and a small set of GPIO pins suited to SOIC-16 board-level designs. The part ships in industrial temperature range (-40 °C to +85 °C or +105 °C per datasheet specifics) in a thru-hole-friendly SOIC-16 wide-body package.
From an architecture standpoint, the device uses a Harvard-style 8-bit datapath with a 16-bit index register, 32 KB address space, and a vectored interrupt structure. The internal 1 kB RAM and 128-byte EEPROM/Flash-info area support small data tables and stack-intensive C programs via the Freescale/NXP CodeWarrior toolchain. An integrated brown-out detector and watchdog improve field robustness.
Typical applications include household appliances, white goods user interfaces, low-end remote controls, small sensor nodes, LED driving boards, toys, and simple motor/relay controllers where cost is the dominant design constraint and 8-bit headroom is sufficient.
When migrating designs, verify VDD tolerance, pinout, and ADC channel mapping against the latest MC9RS08KA8 datasheet (Rev. 4) because NXP has documented PCN-style changes that may differ from earlier revisions. RoHS status should be confirmed at order entry given the part's end-of-life notice.
This page synthesizes distributor pricing, drop-in same-package alternatives within the RS08KA family, lifecycle notes, and practical design considerations that are not aggregated in any single manufacturer document.
Drop-in alternatives for MC9RS08KA8CWG — 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 MC9RS08KA8CWG (same form factor and footprint) — differing in Package, Mounting Type, ADC, Low-Power Modes, Number of I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9RS08KA4CWGR
✅ Drop-In📋 Reference alternative (not in catalog)
MC9RS08KA4CWG
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →MC9RS08KA8CWJ
✅ Drop-In✓ In Stock
$1.68 / Unit
View Datasheet →MC9RS08KB4CSG
✅ Drop-In✓ In Stock
$1.81 / Unit
View Datasheet →MC9RS08KA8CWG Maximum Ratings & Electrical Characteristics
| Core Architecture | RS08 (8-bit, HC08 subset) |
| Core Series | RS08KA |
| Data Bus Width | 8 bit |
| Program Memory (Flash) | 8 KB |
| Maximum CPU Frequency | 20 MHz |
| Supply Voltage (VDD) | 2.5 V to 5.5 V |
| Operating Temperature | -40 C to +85 C (industrial, see datasheet) |
| Package | 16-pin SOIC (SOW) |
| Mounting Type | Surface Mount |
| ADC | Yes (multi-channel, 10-bit) |
| Timers | Yes (MTIM/TPM) |
| Internal Voltage Regulator | Yes |
| Watchdog | Yes (COP) |
| Brown-out Reset | Yes |
MC9RS08KA8CWG Pin Configuration
| Pin 1 | PTA0 / TCLK — GPIO PTA0, alternative TCLK input (timer clock source) |
| Pin 2 | PTA1 — GPIO PTA1 |
| Pin 3 | PTA2 — GPIO PTA2 |
| Pin 4 | PTA3 / RESET — GPIO / bidirectional reset (configuration-dependent) |
| Pin 5 | VDD — Supply voltage input (internal regulator input) |
| Pin 6 | VSS — Ground |
| Pin 7 | PTB0 / ADP0 — GPIO PTB0, alternate ADC channel ADP0 |
| Pin 8 | PTB1 / ADP1 — GPIO PTB1, alternate ADC channel ADP1 |
| Pin 9 | PTB2 / ADP2 — GPIO PTB2, alternate ADC channel ADP2 |
| Pin 10 | PTB3 / ADP3 — GPIO PTB3, alternate ADC channel ADP3 |
| Pin 11 | PTB4 / ADP4 — GPIO PTB4, alternate ADC channel ADP4 |
| Pin 12 | PTB5 — GPIO PTB5 |
| Pin 13 | PTC0 / SDA — GPIO / I2C SDA (peripheral availability per datasheet) |
| Pin 14 | PTC1 / SCL — GPIO / I2C SCL (peripheral availability per datasheet) |
| Pin 15 | BKGD / MS — Background Debug / Mode Select |
| Pin 16 | PTA4 — GPIO PTA4 |
Typical Applications
MC9RS08KA8CWG is suitable for 6 applications: White Goods / Appliance User Interface, Low-End Remote Control Handsets, Toy and Hobby Electronics, Sensor / Monitoring End Nodes, LED Lighting / Indicator Drivers, Small Motor / Relay Control Boards.
White Goods / Appliance User Interface
The MC9RS08KA8CWG fits white-goods user-interface boards because its 8-bit RS08 core handles keypad scan, LED/LCD drive, and simple beeper control with margins to spare. Operating from a 3.3 V or 5 V rail via the integrated regulator, the part eliminates the need for an external LDO in cost-down appliance designs. The 20 MHz core clock supports debounced key matrices and indicator multiplexing without timing issues. Soak-tested industrial temperature variants suit refrigerator and washing-machine cabinet environments, while the 16-SOIC outline picks-and-places cleanly onto single-sided boards.
Recommended
Low-End Remote Control Handsets
Battery-powered remote controls benefit from the MC9RS08KA8CWG's low-power stop modes and internal regulator, which together allow years of operation from a single AAA cell pair. The RS08 core wakes on a port interrupt, scans the keypad, transmits via an external 433 MHz/IR Tx, and returns to sleep within milliseconds. The 8-bit datapath is well-matched to command-decode and rolling-code firmware while the SOIC-16 footprint keeps the BOM lean. Per the MC9RS08KA8 datasheet Rev. 4, deep-stop current is in the single-digit microampere range, ideal for handheld use.
Recommended
Toy and Hobby Electronics
Toys and hobby kits rely on the MC9RS08KA8CWG for its sub-$2 BOM cost, robust GPIO count, and 20 MHz headroom for sound PWM, motor PWM, and simple LED chasers. The integrated brown-out reset and COP watchdog protect against weak battery operation common in toy use. Designers can drop the binary onto internal 8 KB Flash and have plenty of room for multi-mode behaviour. The 16-SOIC outline is lead-free and works with low-temperature hobby reflow profiles, and the toolchain (CodeWarrior) is free for low-volume production.
Recommended
Sensor / Monitoring End Nodes
For distributed analog monitoring nodes (temperature, humidity, simple switch contacts), the MC9RS08KA8CWG's 10-bit ADC, modest 8 KB Flash, and integrated regulator keep the per-node bill of materials to a minimum. The part reads sensors via its ADC channels and reports over a UART to a host MCU or radio. Operating from a 3.3 V LDO derived from a battery or harvesting source, the device supports long cable runs from a 24 V industrial bus when paired with a small buck. Its industrial temperature option suits outdoor and factory-deck use.
Recommended
LED Lighting / Indicator Drivers
LED drivers in decorative and signage use the MC9RS08KA8CWG to run PWM fade tables, button debouncing, and mode selection. The 8-bit RS08 core produces smooth 8-bit PWM via timer channels, and the 20 MHz clock provides high enough frequency to avoid visible flicker on dimmed LEDs. The integrated voltage regulator simplifies 12 V or 24 V input rails down to clean MCU power. With an SOIC-16 package, the controller fits on the same PCB strip as the LED string, keeping assembly simple and cost competitive.
Recommended
Small Motor / Relay Control Boards
Small brushed DC motors and relay-driver boards around home automation and HVAC subsystems are well-served by the MC9RS08KA8CWG. The 5 V-tolerant GPIOs can directly drive small logic-level MOSFETs and optocouplers, while timers manage PWM for variable-speed fans or PID loops. COP watchdog and brown-out reset protect against mains-induced brown-outs common in HVAC cabinets. With 8 KB Flash the controller can host modest lookup tables and persistent state in non-volatile info area, simplifying field service.
Recommended
Recommended Products Summary
Engineering reference data for MC9RS08KA8CWG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9RS08KA4CWGR | MC9RS08KA4CWG | MC9RS08KA8CWJ | MC9RS08KB4CSG |
|---|---|---|---|---|---|
| Package | 16-SOIC (SOW) | 16-SOIC (SOW) - same | 16-SOIC (SOW) - same | 16-SOIC (SOW) - same | 16-SOIC (SOW) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core | RS08 (8-bit) | RS08 (8-bit) - same family | RS08 (8-bit) - same family | RS08 (8-bit) - same die | RS08 (8-bit) - KB family variant |
| Flash Memory | 8 KB | 4 KB (-50%) | 4 KB (-50%) | 8 KB (same) | 4 KB (-50%) |
| Maximum CPU Frequency | 20 MHz | 20 MHz - same | 20 MHz - same | 20 MHz - same | 20 MHz - 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 |
| Series / Family | RS08KA | RS08KA - same | RS08KA - same | RS08KA - same | RS08KB - upgrade variant |
| Lifecycle Status | last_time_buy | last_time_buy | last_time_buy | last_time_buy | active (verify at order) |
| Approx. Unit Price (qty-1) | ≈ $2.75 | ≈ $2.20 (lower) | ≈ $2.20 (lower) | ≈ $2.75 (similar) | ≈ $2.40 |
Key Differentiators
- 8 KB Flash at SOIC-16 with 20 MHz CPU (vs MC9RS08KA4CWG)
- Standard CWG package designation for tube shipping (vs MC9RS08KA8CWJ)
- KA-series peripheral set is more compact and lower cost (vs MC9RS08KB4CSG)
Design Notes
The MC9RS08KA8CWG integrates a low-dropout regulator on-chip, so a single 2.5 V to 5.5 V supply on the VDD pin is sufficient for both the internal core and the I/O domain. Decouple VDD with a 1 uF X7R ceramic close to the pin and a parallel 100 nF for high-frequency noise; keep the ground return short. For battery-powered designs (e.g. remote handsets), use the lowest ICSC trim that meets timing to minimise active current, and verify stop-mode current against the datasheet Rev. 4 values before committing.
The 16-SOIC (wide-body) package leaves room for traces on a single-layer board, but route the BKGD/MS pin away from switching lines and add a small inline resistor (4.7 k) or ferrite if you expect debug-port noise during RF or relay events. Provide a 10 k pull-up on RESET/PTA3 if the configuration fuses assign this pin to reset; otherwise leave it as a GPIO with care for the shared pin role.
Do not exceed 5.5 V on VDD - the integrated regulator and Flash endurance ratings assume 2.5 V-5.5 V. Watch ADC inputs for over-voltage: any analog channel must stay within VDD or use a clamp; the on-chip ESD diodes will forward-conduct if abused. Be aware the part is in last-time-buy - stock up or migrate to an active RS08KA/KB equivalent. Finally, the BKGD/MS pin uses a high-voltage entry sequence during flash programming, so ensure it is not loaded by an external circuit unless that load is tolerant of the entry pulse.
When driving capacitive loads from PTA/PTB GPIO, limit the source/sink current to the datasheet maximum (typically a few mA per pin) to avoid ground-bounce and Flash corruption during in-circuit programming. Use short traces and modest series resistors when the GPIO feeds a longer cable or harness to a relay coil.
Compliance Information
RoHS / REACH / lead-free / halogen-free / conflict-minerals status was not unambiguously stated in the live NXP page snapshot returned by web search. Confirm via manufacturer CoC at order entry, particularly given the part is in last-time-buy and a Discontinuance / Product Change Notice has been issued. AEC-Q100 is not applicable - this is a general-purpose industrial / consumer MCU, not an automotive-qualified part.
