MC68EC040RC20A - 32-bit M68000 MPU 20MHz 179-PGA | NXP
MPN: MC68EC040RC20A ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $95 | $95.00 |
| 10 | $85 | $850.00 |
| 100 | $75 | $7,500.00 |
| 500 | $65 | $32,500.00 |
| 1,000 | $55 | $55,000.00 |
MC68EC040RC20A Overview
A microprocessor (MPU) is the central execution unit of an embedded computer system: it fetches instructions from memory, decodes them, and drives peripherals via address, data, and control buses. The 68k family sits in the same hierarchy as ARM and x86 embedded parts, and the EC040 in particular is a 'cache-only' reduced variant used in legacy VMEbus boards, industrial controllers, and aerospace retrofits where deterministic integer performance and software compatibility outweigh the need for an FPU or hardware memory management.
Key features include 20 MIPS integer throughput at 20 MHz, dual 4 KB on-chip caches, a 32-bit internal data path, Burst mode bus support for filling cache lines, and full M68040 instruction-set compatibility (excluding MMU/FPU opcodes). The 179-pin PGA package supports through-hole socket mounting on a 2.54 mm grid, with 32 address lines, 32 data lines, and dedicated transfer-acknowledge/arbitration pins.
The 'EC' variant removes the MMU and FPU, allowing software to use a flat physical-address model. It is electrically and pin-compatible with the full MC68040 (when the FPU/MMU are not required), making it a common cost-down substitute in mature designs. Operating voltage is 5.0 V, junction temperature range 0C to +70C (commercial grade, 'RC' suffix).
Typical applications include legacy VMEbus single-board computers, industrial automation controllers, aerospace/avionics retrofits, telecom switching line-cards, and embedded instrumentation where existing 68k binary code must be preserved.
When designing with this part, ensure your memory subsystem can supply data at the burst rate, since a cache miss can stall the pipeline. Decoupling and clock-signal integrity are critical at 20 MHz; place bulk and ceramic decoupling capacitors close to the PGA socket pins.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for MC68EC040RC20A — 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 MC68EC040RC20A (same form factor and footprint) — differing in Mounting Type, Package, Address Bus Width, Core Architecture, Manufacturer.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68040RC20A
✅ Drop-In📋 Reference alternative (not in catalog)
MC68LC040RC20A
✅ Drop-In📋 Reference alternative (not in catalog)
MC68EC040RC20B
✅ Drop-In📋 Reference alternative (not in catalog)
MC68EC040RC25A
✅ Drop-In✓ In Stock
$92 / Unit
View Datasheet →MC68EC040RC16A
✅ Drop-In📋 Reference alternative (not in catalog)
MC68EC040FE20A
✅ Drop-In✓ In Stock
$25.5 / Unit
View Datasheet →MC68EC040RC20A Maximum Ratings & Electrical Characteristics
| Manufacturer | NXP Semiconductors (formerly Motorola / Freescale) |
| Product Type | Microprocessor (MPU) |
| Core Architecture | M68000 (68000 family, 68040-derived 'EC' core) |
| Core / Bits | 1 Core, 32-bit |
| Instruction Set | M68040 (MMU/FPU removed in 'EC' variant) |
| Clock Frequency | 20 MHz |
| Performance | 20 MIPS integer (estimated) |
| On-Chip Instruction Cache | 4 KB |
| On-Chip Data Cache | 4 KB |
| FPU | Not present (EC variant) |
| MMU | Not present (EC variant) |
| Address Bus Width | 32-bit |
| Data Bus Width | 32-bit |
| Supply Voltage | 5.0 V (typical) |
| Operating Temperature | 0C to +70C (commercial 'RC' suffix) |
| Package | 179-pin PGA (47.24 x 47.24 mm) |
| Mounting Type | Through-hole PGA socket |
| RoHS Status | Unknown (legacy product, likely non-RoHS) |
| Process Technology | HCMOS |
MC68EC040RC20A 179-pin pga (47.24 x 47.24 mm) Pin Configuration Guide
Pin configuration for MC68EC040RC20A (179-pin 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 MC68EC040RC20A.
Refer to the datasheet for full pin configuration.
Typical Applications
MC68EC040RC20A is suitable for 7 applications: Legacy VMEbus Single-Board Computers, Industrial Automation Controllers, Aerospace and Avionics Retrofits, Telecom Line Cards and Switch Fabrics, Medical Imaging Instrumentation, Embedded Test and Measurement, Network Storage Controllers.
Legacy VMEbus Single-Board Computers
The MC68EC040RC20A is the workhorse CPU of late-1990s VMEbus single-board computers in industrial and avionics systems. Its 20 MHz core, dual 4 KB caches, and 32-bit address/data bus match the VMEbus D32 cycle profile, sustaining 20 MIPS integer throughput on legacy 68k firmware. The 179-pin PGA package drops into standard VME CPU sockets, and the absence of an MMU keeps software in physical-address flat mode, simplifying DMA and shared-memory designs. Decoupling and bus-termination practices from the M68040UM still apply, and Burst-mode line fills help maintain cache coherency across the VMEbus backplane.
Recommended
Industrial Automation Controllers
In factory-floor PLCs and motion controllers, the MC68EC040RC20A provides deterministic 32-bit integer performance with the ruggedness of a PGA socketed part. Its 20 MIPS integer throughput handles real-time ladder-logic interpretation, PID loops, and serial/Ethernet protocol stacks in legacy controllers. The 'RC' commercial temperature grade (0C to +70C) suits most enclosed industrial cabinets; for harsher environments, the 'FE' industrial-grade -40C to +85C variant (MC68EC040FE20A) shares the same pinout. Designers value the absence of an MMU because the OS is typically a simple RTOS or bare-metal scheduler.
Recommended
Aerospace and Avionics Retrofits
The MC68EC040RC20A continues to serve in certified avionics and military retrofit programmes where the 68k binary image is already DO-178 or MIL-STD-1540 qualified and cannot be revalidated on a new processor. Its deterministic instruction timing, 32-bit address space, and pin-grid-array through-hole construction ease board-level qualification. The part's long-term availability through Rochester Electronics and authorised brokers is critical for sustainment programmes spanning decades. Engineers reuse the original M68040 reference designs, scaling only the cooling solution if upgrading to the 25 MHz RC25A variant.
Recommended
Telecom Line Cards and Switch Fabrics
In legacy telecom line cards and TDM switch fabrics, the MC68EC040RC20A performs call-processing, signalling, and OAM&P housekeeping at 20 MIPS. Its 32-bit data path and burst-mode bus sustain high-throughput DMA to TDM framers, while the dual on-chip caches absorb jitter from interrupt-driven packet arrivals. The 'EC' architecture (no MMU) keeps the RTOS footprint small, fitting in tens of KB of SRAM, and the PGA package allows conformal-coated boards to be reworked easily. Memory subsystems typically pair the EC040 with 32-bit EDO DRAM or SRAM banks controlled by the MC68EC040 bus controller signals.
Recommended
Medical Imaging Instrumentation
The MC68EC040RC20A powers the control planes of legacy ultrasound, MRI gradient controllers, and patient-monitoring equipment where reliability and deterministic response are paramount. Its integer throughput handles waveform processing and beam-forming control at 20 MIPS, while the absence of an FPU simplifies safety certification because no floating-point edge cases need to be analysed. The through-hole PGA socket simplifies field serviceability in regulated medical environments. Designers maintain firmware validation on the same silicon revision across the product lifecycle to avoid triggering re-certification.
Recommended
Embedded Test and Measurement
In oscilloscopes, logic analysers, and protocol analysers of the late 1990s and early 2000s, the MC68EC040RC20A provides the integer processing power needed to manage displays, run GPIB/USB stacks, and orchestrate data acquisition. Its 32-bit address space accommodates large waveform buffers, and the dual caches smooth out bursty data flows from ADC front-ends. Test equipment designers often use the 'RC' commercial-grade part inside climate-controlled chassis; the 'FE' industrial variant suits portable instruments. Modern replacements target ColdFire or ARM Cortex-A, but EC040 sustainment programmes remain active.
Recommended
Network Storage Controllers
Legacy RAID controllers and NAS appliances from the late 1990s employed the MC68EC040RC20A as the management CPU for RAID metadata, SCSI/ATA command queuing, and TCP/IP offload coordination. Its 32-bit integer performance and burst-mode bus sustain sequential command streams, while the on-chip caches absorb metadata lookups. The PGA socket allows production rework when field failures occur. Designers appreciated that the absence of an MMU simplified real-time response to storage interrupts. The 20 MHz clock was sufficient for the gigabit-era management plane, not the data plane itself.
Recommended
Recommended Products Summary
Engineering reference data for MC68EC040RC20A — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68040RC20A | MC68LC040RC20A | MC68EC040RC20B | MC68EC040RC25A | MC68EC040RC16A | MC68EC040FE20A |
|---|---|---|---|---|---|---|---|
| Package | 179-pin PGA (47.24x47.24 mm) | 179-pin PGA - same | 179-pin PGA - same | 179-pin PGA - same | 179-pin PGA - same | 179-pin PGA - same | 179-pin PGA - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 25 MHz | 16 MHz | 20 MHz |
| FPU | No (EC variant) | Yes | Yes | No | No | No | No |
| MMU | No (EC variant) | Yes | No | No | No | No | No |
| On-Chip I-Cache / D-Cache | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB |
| Address / Data Bus | 32-bit / 32-bit | 32-bit / 32-bit | 32-bit / 32-bit | 32-bit / 32-bit | 32-bit / 32-bit | 32-bit / 32-bit | 32-bit / 32-bit |
| Operating Temperature | 0C to +70C (commercial) | 0C to +70C | 0C to +70C | 0C to +70C | 0C to +70C | 0C to +70C | -40C to +85C (industrial) |
| Supply Voltage | 5.0 V | 5.0 V | 5.0 V | 5.0 V | 5.0 V | 5.0 V | 5.0 V |
Key Differentiators
- Cost-reduced EC variant without FPU/MMU (vs MC68040RC20A)
- Lower cost than LC040 (FPU retained, MMU removed) (vs MC68LC040RC20A)
- Standard commercial temperature grade at lowest cost (vs MC68EC040FE20A)
Design Notes
Use a high-quality PGA socket (e.g., Augat or Mill-Max) to allow field replacement; the 179-pin grid is a 2.54 mm pitch array. Provide at least 4-layer PCB construction with a dedicated ground plane and 5 V power plane to meet the 20 MHz bus timing budgets. Place bulk electrolytic and 0.1 uF ceramic decoupling capacitors within 25 mm of every VCC/GND pin pair to suppress switching noise.
Route the 32-bit data and 32-bit address buses with controlled impedance (typically 50 ohm to ground) and matched trace lengths to preserve bus timing. The CLK input requires a clean, low-jitter source with a series-termination resistor close to the driver to dampen reflections. Refer to the M68040 User's Manual AC electrical specifications for setup/hold times when designing the memory interface.
The MC68EC040RC20A at 20 MHz with a 5.0 V supply can dissipate up to approximately 2-3 W. Ensure airflow or a heatsink is provided in enclosed chassis; the ceramic PGA package conducts heat through the pin grid into the socket and PCB copper. Measure junction temperature with a thermal couple during worst-case workload qualification, and apply derating if upgrading to the 25 MHz RC25A variant (roughly 25% higher dissipation).
Do not assume software compatibility with full 68040 binaries if FPU opcodes are used - the EC040 raises a line-F emulator trap and software must emulate floating-point operations or be recompiled for integer-only execution. Also confirm supply voltage sequencing: the MC68EC040 requires VCC to ramp monotonically and the reset line to be held until the clock stabilises. Finally, ensure the cache control register is initialised correctly to avoid stale cache lines after warm reset.
Compliance Information
Legacy product predates RoHS; most lots are non-RoHS due to PGA construction. AEC-Q100 not applicable (this is a microprocessor, not an automotive-qualified IC). Confirm compliance per specific lot with supplier.
