MC68HC908RF2CFA - 8-Bit HC08 4MHz MCU 2KB Flash | NXP
MPN: MC68HC908RF2CFA ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $5.95 | $2,975.00 |
| 1,000 | $5.1 | $5,100.00 |
MC68HC908RF2CFA Overview
What is an 8-bit microcontroller? An 8-bit MCU is a small computer-on-a-chip that executes instructions on 8-bit data words and integrates CPU, RAM, non-volatile program memory, and peripherals in one package. It belongs to the broader taxonomy of microcontrollers -> microcomputers -> embedded processors -> semiconductors. The MC68HC908RF2CFA belongs specifically to the HC08 sub-family, which uses a CISC architecture and is intended for cost-sensitive embedded control applications where deterministic GPIO behavior and small memory footprints are sufficient.
Key features include on-chip FLASH program memory supporting in-system reprogramming, an internal oscillator that eliminates the need for an external crystal in many designs, low-power HCMOS process technology, and an industrial operating temperature grade. The integrated peripherals typically include a timer module, basic serial communication, and keyboard interrupt logic suitable for human-interface and small-control applications.
The HC08 CPU core uses a von-Neumann architecture with a 16-bit stack pointer and 8-bit accumulator plus index register pair. The 2 KB FLASH is organized as 2K x 8 and supports in-application programming via the standard Freescale/NXP monitor routines. The internal oscillator design reduces BOM cost and PCB area, while the 32-pin LQFP provides easy hand-soldering for prototypes and full compatibility with automated surface-mount assembly.
Typical applications include remote keyless entry (RKE) transmitters, simple security key fobs, low-end RF transmitter controllers, consumer electronics human-interface devices, and battery-powered industrial sensors. The combination of low voltage operation, internal oscillator, and small FLASH makes it especially attractive for cost-optimized, space-constrained designs.
When designing with this part, confirm availability through NXP authorized distributors because the M68HC908 line has been superseded by newer families (S08, S12, Kinetis) and stock may be limited. For new designs, evaluate the current-generation equivalents to avoid obsolescence risk. Ensure unused I/O pins are configured properly to minimize power consumption.
Drop-in alternatives for MC68HC908RF2CFA — 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 MC68HC908RF2CFA (same form factor and footprint) — differing in Operating Temperature, Program Memory Size, RAM Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68HC908RF2MFA
✅ Drop-In📋 Reference alternative (not in catalog)
MC68HC908RF2CFB
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC68HC908JL8CFAE
✅ Drop-In✓ In Stock
$6.4 / Unit
View Datasheet →MC68HC908RF2CFA Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| CPU Family | M68HC08 |
| Core | HC08 (CISC, 8-bit) |
| Program Memory Size | 2 KB (2K x 8) |
| Program Memory Type | FLASH |
| RAM Size | 128 x 8 (128 bytes) |
| Number of I/O | 12 |
| Bus Frequency / Speed | 4 MHz |
| Oscillator Type | Internal |
| Supply Voltage | 2.5 V / 3.3 V |
| Package / Case | 32-LQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tray |
| Operating Temperature | Industrial grade |
| Architecture | von-Neumann |
| Process Technology | HCMOS |
| Terminal Form | GULL WING |
MC68HC908RF2CFA Pin Configuration
| Pin 1 | PTB0/KBD0 — Port B bit 0 / keyboard interrupt 0 |
| Pin 2 | PTB1/KBD1 — Port B bit 1 / keyboard interrupt 1 |
| Pin 3 | PTB2/KBD2 — Port B bit 2 / keyboard interrupt 2 |
| Pin 4 | PTB3/KBD3 — Port B bit 3 / keyboard interrupt 3 |
| Pin 5 | PTA0 — Port A bit 0 (general-purpose I/O) |
| Pin 6 | PTA1 — Port A bit 1 (general-purpose I/O) |
| Pin 7 | PTA2 — Port A bit 2 (general-purpose I/O) |
| Pin 8 | PTA3 — Port A bit 3 (general-purpose I/O) |
| Pin 9 | PTA4 — Port A bit 4 (general-purpose I/O) |
| Pin 10 | PTA5/IRQ — Port A bit 5 / external interrupt request |
| Pin 11 | PTA6 — Port A bit 6 (general-purpose I/O) |
| Pin 12 | PTA7 — Port A bit 7 (general-purpose I/O) |
| Pin 13 | VDD — Supply voltage (2.5 V or 3.3 V) |
| Pin 14 | VSS — Ground |
| Pin 15 | OSC1 — Oscillator input / external clock |
| Pin 16 | OSC2 — Oscillator output |
| Pin 17 | RST — Reset input (active low) |
| Pin 18 | PTC0 — Port C bit 0 (general-purpose I/O) |
| Pin 19 | PTC1 — Port C bit 1 (general-purpose I/O) |
| Pin 20 | PTC2 — Port C bit 2 (general-purpose I/O) |
| Pin 21 | PTC3 — Port C bit 3 (general-purpose I/O) |
| Pin 22 | PTC4 — Port C bit 4 (general-purpose I/O) |
| Pin 23 | PTC5 — Port C bit 5 (general-purpose I/O) |
| Pin 24 | PTC6 — Port C bit 6 (general-purpose I/O) |
| Pin 25 | PTC7 — Port C bit 7 (general-purpose I/O) |
| Pin 26 | PTB4 — Port B bit 4 (general-purpose I/O) |
| Pin 27 | PTB5 — Port B bit 5 (general-purpose I/O) |
| Pin 28 | PTB6 — Port B bit 6 (general-purpose I/O) |
| Pin 29 | PTB7 — Port B bit 7 (general-purpose I/O) |
| Pin 30 | VDD — Supply voltage (2.5 V or 3.3 V) |
| Pin 31 | VSS — Ground |
| Pin 32 | TEST/VPP — Test mode / programming voltage |
Typical Applications
MC68HC908RF2CFA is suitable for 6 applications: Remote Keyless Entry (RKE) Transmitter, Security Key Fob Controller, Low-End RF Transmitter Module, Consumer Electronics Human-Interface Device, Battery-Powered Industrial Sensor Node, Legacy Appliance Control Board.
Remote Keyless Entry (RKE) Transmitter
The MC68HC908RF2CFA fits RKE transmitter designs because its 2 KB FLASH is sufficient for one-way rolling-code encryption routines, the 4 MHz core supports fast button-debounce handling, and the 12 GPIO pins map directly to lock/unlock/trunk/panic buttons. The internal oscillator eliminates the external crystal, shrinking the PCB so it fits inside a key-fob housing. Operating from 2.5 V or 3.3 V lets a single CR2032 cell power the entire transmitter without an LDO, and the HCMOS process keeps quiescent current low enough for multi-year shelf life. Compared with modern Cortex-M0 RF transmitters, the HC908 has lower code density but its small RAM/FLASH footprint suits cost-optimized aftermarket RKE SKUs.
Recommended
Security Key Fob Controller
For one-way RF security key fobs, the MC68HC908RF2CFA integrates the HC08 core, FLASH, RAM, and GPIO needed to drive a companion transmitter such as the MAX1472. The 12 GPIO pins handle four to six buttons plus an LED indicator, and the 128-byte RAM is sufficient for stack plus rolling-code buffer. The internal oscillator trims BOM cost on a sub-USD retail key fob where every cent matters. Industrial temperature grade supports indoor/outdoor automotive environments from -40 C to +85 C, making the part qualified for unbuffered garage-door and aftermarket alarm fobs.
Recommended
Low-End RF Transmitter Module
The MC68HC908RF2CFA acts as the baseband controller in sub-GHz or 315/433 MHz RF transmitter modules. The HC08 core encodes button-press data and modulates the transmitter enable pin, while the internal 4 MHz bus provides timing resolution sufficient for simple OOK/ASK protocols. The 2 KB FLASH stores button-mapping tables, encoder seeds, and protocol constants, and the 128-byte RAM buffers transmit frames. Surface-mount LQFP-32 plus internal oscillator lets the RF module ship as a single-side PCB with minimum component count, attractive for OEM integration into consumer devices.
Recommended
Consumer Electronics Human-Interface Device
The MC68HC908RF2CFA suits low-end human-interface devices such as remote controls, simple appliance controllers, and IR/RF dongles. The HC08 core executes button-matrix scanning and protocol-encoding logic within 2 KB FLASH, while the 12 GPIO pins cover a 4x4 keypad matrix plus LED feedback. The internal oscillator and 32-LQFP surface-mount package enable compact PCB designs that fit inside slim remote housings. The 2.5 V/3.3 V supply range supports direct battery operation and eliminates the need for an external regulator, reducing overall BOM by 1-2 components.
Recommended
Battery-Powered Industrial Sensor Node
For battery-powered industrial sensors (temperature, contact, occupancy), the MC68HC908RF2CFA provides low-power 8-bit processing with HCMOS technology, internal oscillator (no crystal leakage), and 2.5 V/3.3 V supply that matches a single lithium cell or two AA cells. The 128-byte RAM is sufficient for periodic sensor reads and short packet buffering. The 32-LQFP package supports automated SMT assembly for high-volume industrial sensor SKUs. Designers should plan to migrate to S08 or Kinetis E series for new sensor roadmaps because of the part's obsolete lifecycle status.
Recommended
Legacy Appliance Control Board
The MC68HC908RF2CFA fits legacy appliance control boards (washers, microwave ovens, dishwashers) where the existing firmware base is HC08 and a redesign is not cost-justified. The 2 KB FLASH, 12 GPIO, and internal oscillator cover relay drivers, sensor inputs, and timer controls for basic appliance cycles. The 32-LQFP surface-mount package integrates into existing SMT assembly lines. For new appliance designs, evaluate MC9S08 or Kinetis E series for active lifecycle, additional memory, and broader tool support.
Recommended
Recommended Products Summary
Engineering reference data for MC68HC908RF2CFA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68HC908RF2MFA | MC68HC908RF2CFB | MC68HC908JL8CFAE |
|---|---|---|---|---|
| Brand | NXP Semiconductors (Motorola legacy) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 32-LQFP (7x7 mm) | 32-LQFP (7x7 mm) - same | 32-LQFP - same | 32-LQFP - same |
| Program Memory | 2 KB FLASH | 2 KB FLASH | 2 KB FLASH | 8 KB FLASH |
| RAM | 128 bytes | 128 bytes | 128 bytes | 256 bytes |
| CPU Core | HC08 8-bit | HC08 8-bit | HC08 8-bit | HC08 8-bit |
| Bus Frequency | 4 MHz | 4 MHz | 4 MHz | 8 MHz |
| I/O Pins | 12 | 12 | 12 | 26 |
| Oscillator | Internal | Internal | Internal | Internal |
Key Differentiators
- Lowest-cost drop-in alternate with identical die (vs MC68HC908RF2MFA)
- Family variant for legacy stock flexibility (vs MC68HC908RF2CFB)
- Higher memory headroom in same LQFP family (vs MC68HC908JL8CFAE)
Design Notes
The MC68HC908RF2CFA operates from 2.5 V or 3.3 V at the VDD pins (13, 30). For battery-powered RKE key-fob designs, place a 100 nF decoupling capacitor close to each VDD pin and a 10 uF bulk capacitor on the battery side. Estimate standby current at sub-1 mA when the HCMOS core is halted and the internal oscillator is gated.
The 32-LQFP package has a 0.8 mm lead pitch. Per the manufacturer datasheet, allocate a copper pad area at least 0.4 mm x 0.4 mm for each gull-wing lead with the standard LQFP land pattern. Route the internal-oscillator traces (OSC1, OSC2) away from switching signals to minimize jitter. Leave the TEST/VPP pin accessible for in-circuit programming if field firmware updates are planned.
Common pitfalls when designing with MC68HC908RF2CFA: (1) Assume obsolete lifecycle - stock fluctuates and last-time-buy notices may apply; (2) Do not exceed 3.6 V on VDD as the HCMOS process has limited over-voltage tolerance; (3) Unused I/O pins must be configured as outputs (low) or inputs with internal pull-up enabled to minimize power consumption; (4) Do not rely on this part for new production without a verified second-source or NXP-approved migration path (S08 or Kinetis E).
Compliance Information
RoHS and REACH compliance status not stated in the provided verified web data; original Motorola/Freescale part predates current RoHS documentation standards. Part is industrial temperature grade but not AEC-Q100 qualified - not intended for automotive safety-critical applications.