MC68HRC908JK3CDW - 8-bit HC08 MCU, 4KB Flash, 20-SOIC | NXP
MPN: MC68HRC908JK3CDW ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.5 | $6.50 |
| 10 | $5.85 | $58.50 |
| 100 | $5.2 | $520.00 |
| 500 | $4.65 | $2,325.00 |
| 1,000 | $4.1 | $4,100.00 |
MC68HRC908JK3CDW Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, RAM, and peripheral interfaces into one package. The HC08 family, a successor to the HC05 family, sits within the broader taxonomy of microcontrollers -> embedded processors -> semiconductor ICs. MC68HRC908JK3CDW operates from a 3.3 V or 5 V supply and uses a CISC (Complex Instruction Set Computer) architecture, providing byte- and bit-manipulation instructions useful for control-oriented applications.
Key features include 4 KB of Flash program memory (4K x 8), 128 bytes of on-chip RAM, on-chip LED drive capability, an LVD module for brown-out protection, internal POR, PWM channels, and 15 I/O lines. The HCMOS silicon process enables low-power operation and high noise immunity. The 20-pin SOIC (SO-20) package supports standard surface-mount assembly.
The architecture is based on the M68HC08 CPU core, which shares object code compatibility with the earlier HC05 family while adding new addressing modes and stack instructions. Internal buses, registers, and a small instruction pipeline deliver deterministic interrupt response, which simplifies firmware development for motor control and user-interface tasks.
Typical applications include low-end appliance controls, simple user-interface boards, LED indicator panels, sensor signal conditioning, and small consumer products. Designers select this part when 4 KB of Flash and 15 I/O are sufficient and when cost, rather than peripherals, drives the bill of materials.
A key design consideration is supply voltage: the device is rated for both 3.3 V and 5 V operation, but firmware timing parameters differ between ranges, so consult the datasheet electricals. Also note that the part status is Obsolete, meaning last-time-buy commitments should be confirmed before new design-ins.
This page synthesizes distributor pricing, drop-in same-brand and cross-brand alternatives, application guidance, and design notes not found in the manufacturer datasheet alone, helping engineers migrate off the obsolete MC68HRC908JK3CDW with verified substitutes.
Drop-in alternatives for MC68HRC908JK3CDW — 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 MC68HRC908JK3CDW (same form factor and footprint) — differing in Core Architecture, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68HRC908JK3CDWE
✅ Drop-In📋 Reference alternative (not in catalog)
MC908JK3ECDWE
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →MC908JK3CDWE
✅ Drop-In📋 Reference alternative (not in catalog)
MC68HRC908JL3CDW
✅ Drop-In📋 Reference alternative (not in catalog)
MC68HRC908JK1CDW
✅ Drop-In📋 Reference alternative (not in catalog)
MC68HRC908JK3CDW Maximum Ratings & Electrical Characteristics
| Core Processor | HC08 |
| Core Size | 8-Bit |
| Core Architecture | CISC (M68HC08) |
| CPU Speed | 8 MHz |
| Program Memory Size | 4 KB (4K x 8) |
| Program Memory Type | FLASH |
| RAM Size | 128 x 8 (128 bytes) |
| EEPROM Size | Not specified |
| Number of I/O | 15 |
| Peripherals | LED, LVD, POR, PWM |
| Connectivity | Not specified |
| Supply Voltage | 3.3 V / 5 V |
| Package | 20-SOIC (W) |
| Mounting Type | Surface Mount |
| Part Status | Obsolete |
| Series | HC08 |
| Process Technology | HCMOS |
MC68HRC908JK3CDW Pin Configuration
| Pin 1 | PTA0/ATD0 — Port A bit 0 / ATD input |
| Pin 2 | PTA1/ATD1 — Port A bit 1 / ATD input |
| Pin 3 | PTA2/ATD2 — Port A bit 2 / ATD input |
| Pin 4 | PTA3/ATD3 — Port A bit 3 / ATD input |
| Pin 5 | VDD — Supply voltage (3.3 V or 5 V) |
| Pin 6 | VSS — Ground |
| Pin 7 | OSC1 — Oscillator input / external clock |
| Pin 8 | OSC2 — Oscillator output |
| Pin 9 | RESET — Reset input (active low) |
| Pin 10 | PTB0/TCLK — Port B bit 0 / timer clock input |
| Pin 11 | PTB1/TCH0 — Port B bit 1 / timer channel 0 |
| Pin 12 | PTB2/TCH1 — Port B bit 2 / timer channel 1 |
| Pin 13 | PTB3 — Port B bit 3 |
| Pin 14 | PTB4 — Port B bit 4 |
| Pin 15 | PTB5 — Port B bit 5 |
| Pin 16 | PTC0 — Port C bit 0 |
| Pin 17 | PTC1 — Port C bit 1 |
| Pin 18 | PTC2 — Port C bit 2 |
| Pin 19 | PTC3 — Port C bit 3 |
| Pin 20 | IRQ — External interrupt request |
Typical Applications
MC68HRC908JK3CDW is suitable for 6 applications: Low-End Appliance Control, LED Indicator Panels, Simple User-Interface Boards, Sensor Signal Conditioning, Small Consumer Products, Industrial Timer / Counter Modules.
Low-End Appliance Control
The MC68HRC908JK3CDW's 4 KB Flash, 15 I/O pins, and integrated PWM make it a strong fit for low-end appliance control boards such as simple washing-machine timers, rice cookers, and microwave user-interface panels. Its 3.3 V/5 V supply flexibility lets designers reuse a single PCB across regions with different mains-side rail voltages, and the HC08 CISC core's bit-manipulation instructions simplify direct GPIO control of relays and triacs.
Recommended
LED Indicator Panels
With on-chip LED drive peripherals, the MC68HRC908JK3CDW can directly sink or source LED arrays for status-indicator panels in industrial equipment, vending machines, and consumer appliances. The integrated LED module reduces BOM cost by eliminating external transistor drivers, while the HC08's 8 MHz CPU executes multiplexing routines fast enough to drive 7-segment or dot-matrix displays without flicker.
Recommended
Simple User-Interface Boards
The 15 I/O pins on the MC68HRC908JK3CDW comfortably support 4x4 keypads, rotary encoders, and small LCD character displays found in entry-level user-interface boards. The HC08's CISC instructions speed up scan loops, and the 128-byte RAM is sufficient for key-debounce buffers and LCD refresh data. Designers add a small external character LCD and use PWM to drive backlight brightness, all from a single 5 V rail.
Recommended
Sensor Signal Conditioning
In simple sensor-interface boards for thermistors, photocells, or Hall-effect switches, the MC68HRC908JK3CDW reads analog or digital sensor signals through 15 I/O pins and applies calibration in firmware. The LVD peripheral protects against brown-out when sensor supplies sag, while the POR ensures a clean startup. Its 4 KB Flash stores lookup tables and calibration constants for cost-sensitive IoT edge nodes.
Recommended
Small Consumer Products
Cost-driven consumer gadgets such as remote controls, electronic toys, and personal-care devices use the MC68HRC908JK3CDW because its 4 KB Flash, 128-byte RAM, and PWM/LED peripherals fit the small-footprint BOM. The HC08's low power HCMOS process extends battery life, and the 20-SOIC package is hand-solderable for prototyping. Designers often pair this MCU with a single-cell AA or AAA supply at 3.3 V.
Recommended
Industrial Timer / Counter Modules
The MC68HRC908JK3CDW's on-chip PWM and timer channels make it suitable for industrial timer/counter modules such as conveyor dwell-time controllers, pump cycle counters, and process-on timers. The 8 MHz CPU executes timing algorithms deterministically thanks to the HC08 interrupt structure, and the LVD peripheral shuts the output down safely during brown-out events. The 20-SOIC package fits standard DIN-rail timer board layouts.
Recommended
Recommended Products Summary
Engineering reference data for MC68HRC908JK3CDW — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68HRC908JK3CDWE | MC908JK3ECDWE | MC908JK3CDWE | MC68HRC908JL3CDW | MC68HRC908JK1CDW |
|---|---|---|---|---|---|---|
| Package | 20-SOIC (W) | 20-SOIC (W) - same | 20-SOIC (W) - same | 20-SOIC (W) - same | 20-SOIC (W) - same | 20-SOIC (W) - same |
| Brand | NXP Semiconductors (formerly Freescale/Motorola) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core Processor | HC08 (8-bit CISC) | HC08 | HC08 | HC08 | HC08 | HC08 |
| CPU Speed | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 8 MHz |
| Program Memory (Flash) | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB | 1.5 KB |
| RAM Size | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 128 bytes |
| Number of I/O | 15 | 15 | 15 | 15 | 23 | 15 |
| Supply Voltage | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Legacy HC08 family with established toolchain support (vs MC908JK3CDWE)
- Higher Flash density than JK1 variant (vs MC68HRC908JK1CDW)
- More compact I/O count fits low-pin-count designs (vs MC68HRC908JL3CDW)
Design Notes
The MC68HRC908JK3CDW operates from a single 3.3 V or 5 V supply. Add a 100 nF decoupling capacitor as close as possible to the VDD pin (pin 5) and a bulk 10 uF tantalum or aluminum capacitor near the supply entry to suppress digital switching noise. The internal POR holds the device in reset until VDD crosses the POR threshold, so a clean rising supply is essential for reliable startup.
Because the part is marked Obsolete by NXP, do not design it into new production boards without a confirmed last-time-buy plan. Designers should evaluate modern NXP S08 replacements such as the MC9S08QD4J2MSCR or Kinetis E MCUs (e.g., MKE04Z64VLK4R) for new designs. When migrating, note that the HC08 CISC instruction set is not binary-compatible with the S08 core; firmware must be recompiled and re-validated.
Route the OSC1/OSC2 traces short and symmetric, and place the crystal/ceramic resonator within 5 mm of the pins to minimize parasitic capacitance and EMI. Keep the RESET line free of noise by adding a 10 kohm pull-up to VDD and a 100 nF capacitor to VSS for debounce. Avoid routing high-current switching traces adjacent to the analog-capable PTA pins to prevent digital noise coupling into measurements.
Compliance Information
Compliance status not explicitly listed in the verified web data; the W suffix on the part number suggests Pb-free terminal finish per Freescale/NXP convention, but RoHS/REACH statements were not found in the provided snippets. AEC-Q100 not applicable - this is a general-purpose MCU not qualified for automotive safety.
