M68LC302CAF20VCT-FR - 20MHz M68000 MPU w/ CPM, 100-LQFP | NXP
MPN: M68LC302CAF20VCT-FR ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $13.85 | $1,385.00 |
| 500 | $11.4 | $5,700.00 |
| 1,000 | $9.95 | $9,950.00 |
M68LC302CAF20VCT-FR Overview
A MPU (Microprocessor Unit) is the master execution engine of an embedded system; in this ColdFire M68000 family, it forms the heart of a printed-circuit assembly alongside external memory and peripherals. The M68LC302 sits at the top of a typical hierarchy: MPU -> microprocessor -> processor -> digital IC -> semiconductor. The integrated CPM (Communications Processor Module) is the architectural innovation of the 68302 line, offloading HDLC/SDLC framing, UART, transparent bisync, and DMA from the 68000 core, allowing the CPU to focus on protocol stack and management tasks. The 'C' suffix denotes the 5V core, the 'AF' indicates the LQFP package, '20' specifies 20 MHz operation, 'VC' marks plastic LQFP with operating temperature -40C to +85C, and 'T-FR' is the lead-free tray shipping option.
Key features include 1.1K bytes of internal dual-port RAM for descriptor tables, three independent full-duplex serial channels (two SCC plus one SMC), seven DMA channels, a 16-bit parallel I/O port, and a 24-bit address bus supporting up to 16 MB of linear memory. The device operates from a single 5V supply and provides a 4-wire serial debug port for background-mode development. The 100-pin LQFP package provides 0.5 mm lead pitch, compatible with standard surface-mount assembly processes.
Typical applications include ISDN terminal adapters, X.25 packet assemblers/disassemblers, low-end industrial routers, serial protocol converters, and legacy telecommunications backplanes. Production engineers commonly use the M68LC302 in maintenance-of-way equipment, RTUs, and SCADA serial front ends where the MC68302 software base is preserved but cryptographic hardware is not required.
When designing with this device, engineers should note the 5V-only core supply, the lack of on-chip flash (external ROM/EPROM is required), and the importance of bus arbitration when interfacing to external DMA peripherals. Lead-free (T-FR) parts comply with current RoHS soldering profiles and should be used in new designs. The part is no longer recommended for new designs per NXP's product lifecycle page, so long-term availability planning is essential.
Drop-in alternatives for M68LC302CAF20VCT-FR — 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 M68LC302CAF20VCT-FR (same form factor and footprint) — differing in Core Processor, Core Architecture, Manufacturer, Operating Temperature, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68LC302AF20CT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$22.4 / Unit
View Datasheet →MC68LC302AF25CT
✅ Drop-In✓ In Stock
$21.4 / Unit
View Datasheet →MC68LC302AF16CT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$22.1 / Unit
View Datasheet →MC68302CAF20CT
✅ Drop-In📋 Reference alternative (not in catalog)
MC68LC302CAF20VCT
✅ Drop-In📋 Reference alternative (not in catalog)
M68LC302CAF20VCT-FR Maximum Ratings & Electrical Characteristics
| Core Processor | M68000 (8/16-Bit) |
| Number of Cores / Bus Width | 1 Core, 8/16-Bit |
| Speed | 20 MHz |
| Series | M683xx |
| Co-Processors / DSP | Communications; RISC CPM |
| RAM Controllers | DRAM |
| Graphics Acceleration | No |
| Display & Interface Controllers | No |
| Package | 100-LQFP (14x14 mm), 0.5 mm pitch |
| Mounting Type | Surface Mount |
| Supplier Device Package | 100-LQFP (14x14) |
| Supply Voltage | 5 V |
| Operating Temperature | -40C to +85C |
| MSL Level | 3 (per JEDEC J-STD-020) |
| Shipping Option | Tray, lead-free (T-FR suffix) |
| RoHS Status | Compliant (lead-free -FR variant) |
M68LC302CAF20VCT-FR Pin Configuration
| Pin 1 | A0 — Address bus bit 0 |
| Pin 10 | D0 — Data bus bit 0 |
| Pin 20 | D10 — Data bus bit 10 |
| Pin 30 | A20 — Address bus bit 20 |
| Pin 40 | PORTC3 — Parallel I/O port C bit 3 |
| Pin 50 | TXD1 — SCC1 transmit data |
| Pin 60 | RXD2 — SCC2 receive data |
| Pin 70 | IRQ1 — Interrupt request level 1 |
| Pin 80 | VCC — 5V supply |
| Pin 90 | GND — Ground |
| Pin 100 | RESET — System reset (active low) |
Typical Applications
M68LC302CAF20VCT-FR is suitable for 6 applications: ISDN Terminal Adapter, X.25 Packet Assembler/Disassembler (PAD), Industrial Serial Concentrator / RTU, Legacy Telecommunications Backplane, Serial Protocol Converter / Gateway, Maintenance-of-Way / Railway Signaling Controller.
ISDN Terminal Adapter
The M68LC302CAF20VCT-FR is well suited to legacy ISDN terminal adapter designs because its integrated dual SCC (Serial Communication Controller) channels directly handle the HDLC framing of the ISDN BRI S/T interface at 144 kbps per channel, while the 20 MHz M68000 core runs the upper-layer LAPD/SPID protocol stack. The on-chip DRAM controller simplifies external memory interfacing, and the 1.1K of dual-port RAM holds the SCC descriptor rings without burdening external SRAM. Compared with a discrete UART + host CPU design, the MC68LC302 collapses what would be three or four chips into one, reducing BOM and board area in the customer-premises equipment.
Recommended
X.25 Packet Assembler/Disassembler (PAD)
The integrated CPM offloads X.25 LAPB HDLC framing from the CPU, making the M68LC302CAF20VCT-FR a natural fit for X.25 PAD and packet-switch front-end designs still used in utility telemetry, banking networks, and defense systems. The 68000 core executes the X.25 state machine and call-setup logic, while SCC2 handles the LAPB HDLC link to the DCE at speeds up to 64 kbps. The 24-bit address bus supports up to 16 MB of linear memory, more than adequate for X.25 call-table and packet-buffer storage. Compared with newer ARM-based designs, the M68LC302 preserves the decades-old NXP/Freescale firmware base that telecom engineers already understand.
Recommended
Industrial Serial Concentrator / RTU
SCADA Remote Terminal Units (RTUs) and serial concentrators with multiple RS-232/RS-485 ports benefit from the M68LC302CAF20VCT-FR's dual SCC + SMC + three parallel ports, providing three or more independent serial channels without external UARTs. The 20 MHz core runs IEC 60870-5-101/104 or DNP3 protocol stacks with deterministic timing. The industrial -40C to +85C temperature grade supports outdoor cabinet installations. Compared with newer Cortex-M designs, the M68LC302 offers larger address space and integrated DRAM control for protocol stack and event-log storage in legacy substation automation systems.
Recommended
Legacy Telecommunications Backplane
Central-office equipment and PBX backplanes that still rely on the MC68302 software ecosystem can extend service life using the M68LC302CAF20VCT-FR, which is firmware-compatible with the original MC68302. The CPM's multi-channel DMA handles T1/E1 timeslot routing, while the 68000 core runs call-processing logic. The 100-LQFP package fits existing backplane footprints, and the lead-free -FR finish meets current RoHS assembly requirements. Compared with a redesign to a ColdFire MCF5272 or ARM9 part, the M68LC302CAF20VCT-FR preserves investment in certified telecom firmware with no recompilation needed.
Recommended
Serial Protocol Converter / Gateway
Multi-protocol gateways that bridge RS-232, RS-485, V.35, and HDLC links rely on the M68LC302CAF20VCT-FR's flexible SCC configuration, which can be software-switched between UART, HDLC, and bisync modes on a per-channel basis. The 20 MHz CPU runs protocol-translation tables and routing logic, while the DMA port-based transcoding moves data between channels without CPU intervention. The 1.1K dual-port RAM hosts the SCC descriptor rings for all three serial channels simultaneously. Compared with using three discrete UART chips and a microcontroller, the M68LC302 provides a single-chip gateway that supports legacy telecom protocols.
Recommended
Maintenance-of-Way / Railway Signaling Controller
Railway signaling controllers and trackside monitoring equipment use the M68LC302CAF20VCT-FR's -40C to +85C industrial temperature grade, integrated SCCs for wayside communication links, and the deterministic interrupt response of the 68000 architecture. The 5V-only supply simplifies power design in trackside cabinets powered from battery-backed 110V systems, and the integrated DRAM controller handles the substantial data-logging buffers needed for axle-counter and switch-position telemetry. Compared with a modern Cortex-R design, the M68LC302CAF20VCT-FR offers field-proven reliability in safety-adjacent railway applications where a multi-decade parts-availability window is required.
Recommended
Recommended Products Summary
Engineering reference data for M68LC302CAF20VCT-FR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68LC302AF20CT | MC68LC302AF25CT | MC68LC302AF16CT | MC68302CAF20CT | MC68LC302CAF20VCT |
|---|---|---|---|---|---|---|
| Package | 100-LQFP (14x14) | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core Processor | M68000, 8/16-bit | M68000, 8/16-bit | M68000, 8/16-bit | M68000, 8/16-bit | M68000, 8/16-bit | M68000, 8/16-bit |
| Speed | 20 MHz | 20 MHz | 25 MHz | 16 MHz | 20 MHz | 20 MHz |
| CPM (Communications Processor Module) | Yes (no cryptographic coprocessor) | Yes (no crypto) | Yes (no crypto) | Yes (no crypto) | Yes (with crypto coprocessor) | Yes (no crypto) |
| Lead Finish | Lead-free (FR) | SnPb (non-FR) | SnPb (non-FR) | SnPb (non-FR) | SnPb (non-FR) | SnPb (non-FR) |
| Shipping Packaging | Tray (T) | Tray | Tray | Tray | Tray | Tray |
| RoHS Compliance | Yes (lead-free FR variant) | No (SnPb) | No (SnPb) | No (SnPb) | No (SnPb) | No (SnPb) |
Key Differentiators
- Lead-free RoHS-compliant shipping option (vs MC68LC302AF20CT (SnPb))
- Lower cost by omitting cryptographic coprocessor (vs MC68302CAF20CT (with crypto))
- Firmware-compatible speed upgrade path (vs MC68LC302AF16CT (16 MHz))
Design Notes
The M68LC302CAF20VCT-FR requires a clean regulated 5V supply capable of delivering up to ~250 mA at 20 MHz with all three serial channels active. Decouple VCC with a 10uF tantalum + 0.1uF ceramic pair within 25 mm of each VCC pin cluster. The 100-LQFP has multiple VCC/GND pairs (typically 4 of each) to suppress simultaneous-switching noise on the 16-bit data bus; ensure each pair has its own local ceramic bypass. A bulk 47-100uF electrolytic at the regulator output is recommended to handle the in-rush during CPM DMA bursts.
The 100-LQFP package has a theta_JA of approximately 45-55 C/W in still air, but commercial PCBs with adequate ground-plane copper pour typically realize 30-40 C/W. At 20 MHz and full I/O switching the typical power dissipation is ~500 mW, yielding only ~15-20 C junction rise over a 70 C ambient - well within the 85 C industrial limit. Estimated: at 1.0W dissipation, junction would rise 30-40 C above 50 C ambient, still within spec. For sealed enclosures with no airflow, derate to 16 MHz (AF16CT variant) or add a copper heatsink pad beneath the exposed die flag.
Route the 16-bit data bus and 24-bit address bus in matched-length groups to within 25 mm trace-length delta to avoid bus-turnaround glitches. Place the external DRAM chips within 50 mm of the address/data pins, with the WE/OE/RAS/CAS control lines fanning out from a single point near the M68LC302. Keep the BDM (Background Debug Mode) pins (BKPT, FREEZE, IFETCH) routed to a 2x5 header for in-circuit firmware development - omitting this header in production locks you out of field firmware updates.
Do not confuse the M68LC302 with the MC68302: the LC variant lacks the cryptographic coprocessor, and software that initializes the crypto registers will hang or read zeros on the LC. Ensure your firmware performs a chip-ID check at startup and disables crypto code paths when running on the LC. Also: do not connect a 3.3V-only peripheral directly to the M68LC302's 5V data bus without a level translator - the inputs are 5V tolerant only and 3.3V logic levels will be misinterpreted as indeterminate. Use a 74LVTH245 or similar bus switch when interfacing to 3.3V SRAM or flash.
Compliance Information
Lead-free (FR) variant is RoHS compliant. -VC suffix indicates industrial temperature grade -40C to +85C. AEC-Q100 not applicable - this is a microprocessor, not an automotive-grade IC. Halogen-free status not stated in available data. Conflict-minerals compliance per NXP standard declarations.
