MC68LC040RC25A - 32-bit 25 MHz M680x0 MPU, 179-PGA | NXP
MPN: MC68LC040RC25A ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $89.5 | $89.50 |
| 10 | $82.3 | $823.00 |
| 100 | $75 | $7,500.00 |
| 500 | $68.4 | $34,200.00 |
| 1,000 | $62 | $62,000.00 |
MC68LC040RC25A Overview
What is an MPU? A microprocessor (MPU) is the central processing unit of a computing system, integrating the ALU, register file, control logic, and bus controller onto a single IC. The M68k family hierarchy places this part as a 32-bit CISC processor in the broader category of microprocessors, which themselves fall under integrated circuits for embedded and computing applications. Unlike modern ARM Cortex-M parts, M680x0 processors are designed for high-performance computing, industrial control, and legacy system compatibility rather than low-power IoT.
Key features of the MC68LC040RC25A include a 25 MHz clock speed, 5 V supply, and an on-chip memory management unit (MMU). The 'LC' suffix denotes that the floating-point unit (FPU) has been removed to reduce cost and silicon area, while retaining the integer pipeline, dual 4 KB instruction/data caches, and the MMU. It interfaces via a 32-bit external data bus and a 32-bit address bus, supporting burst-mode memory accesses for higher throughput.
Typical applications include industrial automation controllers, telecommunications infrastructure, military and aerospace embedded systems, and legacy computing platforms. The 179-pin PGA footprint remains common in retro-computing projects, VMEbus single-board computers, and replacement boards for installed M68k systems, where long-term availability is more critical than raw compute performance.
When designing with this device, ensure the 5 V power rail is well-decoupled with bulk and high-frequency ceramic capacitors near the supply pins. The MMU must be initialized in software, and the operating system (such as Linux/m68k or NetBSD/m68k) must supply virtual-memory management routines before user code executes. Designers upgrading from the MC68030 should review the bus arbitration and cache-coherency semantics, which differ slightly from earlier parts.
Drop-in alternatives for MC68LC040RC25A — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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Request AlternativesMC68LC040RC25A Maximum Ratings & Electrical Characteristics
| Processor Type | M680x0 32-Bit |
| Clock Speed | 25 MHz |
| Supply Voltage | 5 V |
| Number of Cores | 1 |
| Data Bus Width | 32-bit |
| Address Bus Width | 32-bit |
| MMU | Present |
| FPU | Not present (LC variant) |
| On-chip Cache | 4 KB instruction + 4 KB data |
| Package / Case | 179-PGA (47.24 x 47.24 mm) |
| Mounting Type | Through-Hole (PGA) |
| Packaging | Tray |
| Lead Free Status | Lead Free |
| RoHS Status | RoHS Compliant |
MC68LC040RC25A 179-pga (47.24 x 47.24 mm) Pin Configuration Guide
Pin configuration for MC68LC040RC25A (179-pga (47.24 x 47.24 mm) 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 MC68LC040RC25A.
Refer to the datasheet for full pin configuration.
Typical Applications
MC68LC040RC25A is suitable for 6 applications: Legacy Industrial Control Systems, VMEbus Single-Board Computers, Retro-Computing and Emulation Hosts, Telecommunications Switching Systems, Military and Aerospace Embedded Computing, Medical Imaging and Diagnostic Equipment.
Legacy Industrial Control Systems
The MC68LC040RC25A is widely deployed in legacy factory automation, CNC controllers, and SCADA systems where the original M68k design must be maintained for decades. Its 25 MHz integer performance, MMU support, and 5 V supply match the original design parameters, while the 179-pin PGA socketed package allows direct board-level replacement without PCB rework. Engineers favor this part for sustaining installed production lines where re-qualifying a new processor would be prohibitively expensive.
Recommended
VMEbus Single-Board Computers
The MC68LC040RC25A powered an entire generation of VMEbus single-board computers used in telecommunications, defense, and aerospace systems. Its 32-bit data bus, MMU for virtual memory, and 5 V tolerance make it directly compatible with classic VMEbus backplanes. The 25 MHz variant was commonly chosen for lower-power slots, while 33 MHz and 40 MHz parts were used on CPU boards needing higher throughput for protocol processing.
Recommended
Retro-Computing and Emulation Hosts
Hobbyists and educational users employ the MC68LC040RC25A in retro-computing projects, Atari-compatible accelerators, and FPGA soft-core host systems. The MMU allows real Linux/m68k and NetBSD/m68k installations, while the 25 MHz clock is adequate for authentic legacy software performance. The 179-pin PGA footprint is reproduced by open-hardware projects, enabling modern PCB designs to host this classic processor.
Recommended
Telecommunications Switching Systems
Telecommunications switching fabrics of the 1990s relied on the MC68LC040RC25A for control-plane processing. Its deterministic interrupt latency, MMU for process isolation, and 5 V supply tolerance match telecom equipment power budgets. Although long obsolete for greenfield designs, this part remains in service in installed central-office equipment where replacement requires line-card re-qualification.
Recommended
Military and Aerospace Embedded Computing
Military and aerospace programs designed in the 1990s standardized on the MC68LC040RC25A for embedded computing modules, avionics databuses, and weapons-system controllers. Its established reliability, mature software ecosystem, and ability to run hardened real-time operating systems made it a defense-industry favorite. Long-term support contracts ensure continued availability for sustainment programs even as commercial production winds down.
Recommended
Medical Imaging and Diagnostic Equipment
Medical imaging modalities including ultrasound carts, CT scanner controllers, and patient monitoring systems employed the MC68LC040RC25A during the 1990s and early 2000s. Its deterministic execution, real-time interrupt capability, and certified long-term availability supported medical-device regulatory pathways. The 179-pin PGA package allowed easy board replacement during field service, and the LC variant's lower cost fit budget-constrained diagnostic equipment.
Recommended
Recommended Products Summary
Engineering reference data for MC68LC040RC25A — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68LC040RC33A | MC68LC040RC25B | MC68040RC25A | MC68EC040RC25A | MC68040RC25B |
|---|---|---|---|---|---|---|
| Package | 179-PGA (47.24 x 47.24 mm) | 179-PGA - same | 179-PGA - same | 179-PGA - same | 179-PGA - same | 179-PGA - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Clock Speed | 25 MHz | 33 MHz | 25 MHz | 25 MHz | 25 MHz | 25 MHz |
| MMU | Yes | Yes | Yes | Yes | No (EC variant) | Yes |
| FPU | No (LC variant) | No | No | Yes | No | Yes |
| Supply Voltage | 5 V | 5 V | 5 V | 5 V | 5 V | 5 V |
| Data Bus Width | 32-bit | 32-bit | 32-bit | 32-bit | 32-bit | 32-bit |
| RoHS Compliance | Compliant | Compliant | Compliant | Compliant | Compliant | Compliant |
Key Differentiators
- MMU included for virtual-memory operating systems (vs MC68EC040RC25A)
- Lower cost by omitting FPU (vs MC68040RC25A)
- Same-package 33 MHz upgrade path (vs MC68LC040RC33A)
Design Notes
The MC68LC040RC25A requires a stable 5 V supply with sufficient transient handling. Decouple each VCC pin with a 0.1 uF ceramic capacitor placed within 5 mm of the pin, and add bulk 10-47 uF tantalum or polymer capacitors near the PGA socket. Power-rail sequencing is not required (single rail), but inrush current during power-up can exceed 1 A on a hot cache refill; ensure the regulator has adequate headroom.
The 179-pin PGA package has moderate thermal dissipation (~30 C/W theta_JA in still air), and at 25 MHz the M68k core dissipates roughly 2-3 W. Estimated: at 25 MHz with 5 V VCC and typical CMOS switching activity, junction temperature rises approximately 60-90 C above ambient. Ensure adequate airflow in chassis designs, especially in sealed industrial enclosures.
When migrating from MC68030, note that the MC68LC040RC25A requires initialization of the cache and MMU before user code executes. The reset exception vector at 0x00000000 must contain a valid SSP and PC, and the cache control register (CACR) must be programmed to enable instruction and data caches. Skipping these steps results in mysterious boot failures or stalled execution.
The 32-bit address and data buses must be length-matched within 25 mm on the PCB to preserve bus timing at 25 MHz. Place termination resistors (typically 33 ohm) on the data bus only if the bus length exceeds 100 mm or if multiple memory banks are populated. Clock distribution should use a single driver with matched trace lengths to the CLK pin to avoid skew.
Compliance Information
RoHS compliant and lead-free per distributor datasheet. AEC-Q100 not applicable - this is a microprocessor, not an automotive-qualified IC. REACH and halogen-free status not explicitly stated in verified data.
