MC68EN302AG20BT - 20MHz Ethernet 68K MPU, 144-LQFP | NXP
MPN: MC68EN302AG20BT ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $48.92 | $48.92 |
| 10 | $42.5 | $425.00 |
| 100 | $36.75 | $3,675.00 |
| 500 | $31.2 | $15,600.00 |
| 1,000 | $26.84 | $26,840.00 |
MC68EN302AG20BT Overview
An embedded microprocessor (MPU) is an integrated processor designed to be the central computing element of an embedded system, combining a CPU, on-chip peripherals, and memory control in a single device. Within the broader hierarchy, the MC68EN302 sits in the sub-family of integrated communications processors, descended from the Motorola/Freescale 683xx family of M68K CPUs - a product lineage that evolved from the MC68000 microprocessor introduced in 1979. The device is intended for embedded networking equipment where deterministic serial communications, on-chip Ethernet MAC, and low BOM cost outweigh raw compute throughput.
Key features include an M68000-family CPU core running at 20 MHz, three independent SCC serial channels (usable for UART, HDLC, BISYNC, transparent modes), a separate Ethernet channel with full IEEE 802.3 MAC support and on-chip transmit/receive descriptors that offload bus bandwidth, on-chip DRAM controller, timers, parallel I/O, and interrupt controller. The Ethernet channel supports up to 10 Mbps data rates and uses the "68302" style programming model familiar to legacy firmware developers.
Architecturally, the EN302 separates the CPU-side system bus from the peripheral-side bus, so descriptor-based DMA engines move packet data between the Ethernet channel and system memory without CPU intervention. This dual-bus design is critical for sustaining 10 Mbps line-rate throughput while leaving CPU cycles available for protocol processing (TCP/IP stack, PPP, or proprietary industrial protocols) running from external memory.
Typical applications include industrial Ethernet routers, ISDN terminal adapters, legacy serial-to-Ethernet protocol converters, factory automation gateways, point-of-sale terminals, and telecom access equipment. The on-chip Ethernet MAC plus multi-protocol SCCs make it a single-chip solution for designs that previously required a discrete CPU plus external Ethernet controller plus UART/HDLC ASIC.
When designing with this part, verify that firmware is rebuilt against the 68302 programming model and that the BSD-style Ethernet drivers target the on-chip descriptor ring interface. Supply voltage, junction temperature, and DRAM controller timing parameters not explicitly listed in this product page should be confirmed against the manufacturer datasheet before board bring-up.
This page synthesizes distributor stock data, key parametric differences versus other M68K members, and practical design considerations specific to the EN302 variant - information not aggregated on any single manufacturer or distributor product page.
Drop-in alternatives for MC68EN302AG20BT — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68EN302AG16BTA
✅ Drop-In📋 Reference alternative (not in catalog)
MC68EN302AG25BT
✅ Drop-In📋 Reference alternative (not in catalog)
MC68302AG20B
✅ Drop-In📋 Reference alternative (not in catalog)
MC68EN302AG20BT Maximum Ratings & Electrical Characteristics
| Product Type | Integrated Multi-Channel Communications Processor (MPU) |
| Series | M683xx |
| Core Processor | M68000 |
| Number of Cores | 1 |
| Data Bus Width | 8/16-Bit |
| Max Clock Frequency | 20 MHz |
| On-Chip Ethernet | 10 Mbps, IEEE 802.3 compliant |
| Serial Communications Channels (SCC) | 3 (UART, HDLC, BISYNC, transparent) |
| Memory Controller | DRAM controller on-chip |
| Package | 144-LQFP (20x20 mm) |
| Mounting Type | Surface Mount |
| Graphics Acceleration | No |
| Display & Interface Controllers | None |
| Part Status | Obsolete (per datasheet sources) |
MC68EN302AG20BT 144-lqfp (20x20 mm) Pin Configuration Guide
Pin configuration for MC68EN302AG20BT (144-lqfp (20x20 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 MC68EN302AG20BT.
Refer to the datasheet for full pin configuration.
Typical Applications
MC68EN302AG20BT is suitable for 6 applications: Industrial Ethernet Router / Gateway, ISDN Terminal Adapter / Modem, Serial-to-Ethernet Protocol Converter, Point-of-Sale (POS) Terminal, Telecom Access Equipment, Factory Automation Cell Controller.
Industrial Ethernet Router / Gateway
The MC68EN302AG20BT was designed for industrial Ethernet gateways where a single chip must bridge 10 Mbps Ethernet to multiple legacy serial lines simultaneously. Its on-chip IEEE 802.3 MAC plus three SCCs (UART/HDLC/BISYNC) let a designer replace a discrete CPU + external Ethernet controller + dual UART ASIC with one BGA-equivalent 144-LQFP part. At 20 MHz the M68000 core runs typical embedded IP stacks (uIP, lwIP ported) at multi-Mbps throughput because on-chip descriptors offload per-packet DMA. The DRAM controller interfaces directly to commodity 16-bit EDO DRAM, keeping BOM cost low for industrial-grade gateways. For protocol-rich SCADA gateways converting Modbus TCP to Modbus RTU over RS-232/485, the three SCCs handle up to three independent serial masters concurrently.
Recommended
ISDN Terminal Adapter / Modem
In late-1990s/early-2000s ISDN terminal adapters, the MC68EN302AG20BT paired with an external ISDN transceiver (Siemens/PEC) to deliver TA, router, and modem aggregation functions on a single board. The three SCCs handle ISDN D-channel HDLC framing, V.110 rate adaptation, and V.90 analog-modem control simultaneously. The 20 MHz M68000 core executes the full V.120 transparent PPP stack and V.42bis compression without external bus-master DMA. Its DRAM controller supports the burst-mode page mode of 16-bit EDO used in TA reference designs. Reference designs of that era used the EN302 with external 10Base-T magnetics and a single 10 Mbps Ethernet port for SOHO-router functionality.
Recommended
Serial-to-Ethernet Protocol Converter
For industrial protocol bridge applications - serial EIA-232/422/485 ASCII, Modbus RTU, or proprietary SCADA frames converted to Ethernet TCP/IP - the MC68EN302AG20BT is a single-chip solution. Each SCC can be programmed independently into UART mode at 115.2 kbps to 1 Mbps, while the Ethernet channel runs 10 Mbps full duplex into the on-chip descriptor ring. The host CPU handles protocol stack and conversion logic on the M68000 core; descriptor-based DMA keeps the on-chip data path moving without CPU interrupt overhead. Typical reference designs use one EN302 per multi-channel serial server with up to three serial ports plus one Ethernet uplink, fitting in a DIN-rail industrial enclosure. Lower 16 MHz speed grades allow cost-down SKUs of the same product.
Recommended
Point-of-Sale (POS) Terminal
POS terminals of the late 1990s integrated cash register, payment-terminal, receipt printer, and back-office Ethernet connectivity in one enclosure. The MC68EN302AG20BT was a popular processor for this role because the Ethernet channel handled 10 Mbps back-office sync, while the SCCs drove the receipt printer (UART), the magnetic-stripe reader (UART/HDLC), and the customer display (UART). The M68000 core's deterministic interrupt latency ensured sub-millisecond response to card-reader events, and the on-chip DRAM controller supported 4-16 MB of EDO DRAM for transaction logs. The 144-LQFP package enabled single-sided PCB layouts suitable for thin-profile terminal housings. The same chip platform supports both high-volume low-end (16 MHz) and feature-rich (20 MHz) variants by speed grade.
Recommended
Telecom Access Equipment
Access multiplexers, channel banks, and small-DLC (digital loop carrier) equipment that aggregate multiple E1/T1 lines into a single Ethernet uplink used the MC68EN302AG20BT as the protocol-conversion engine. The SCCs in HDLC mode handle per-timeslot bit-stream multiplexing at 2.048 Mbps for E1 or 1.544 Mbps for T1, while the Ethernet channel provides 10 Mbps uplink to the central office. The on-chip DRAM controller interfaces the buffer memory required for jitter-tolerant time-slot reassignment. Each SCC's independent baud-rate generator and per-channel DMA enable true multi-line concurrency without CPU intervention. Reference designs of that era (e.g., early 2000s MDU/MTU gateways) used 16-25 MHz EN302 variants based on feature mix.
Recommended
Factory Automation Cell Controller
On the factory floor, MC68EN302AG20BT-based cell controllers aggregate sensor data from multiple fieldbuses (DeviceNet, Profibus-DP's UART layer, Modbus RTU) and forward it to Ethernet/IP or Modbus TCP backbones. Each SCC operates as an independent master on a separate fieldbus segment with up to 1 Mbps RS-485 baud rates, while the on-chip Ethernet MAC sustains 10 Mbps sustained traffic to the supervisor PLC. The M68000 core's small footprint RTOS port (uClinux, VxWorks 68K) supports deterministic command-and-response cycles under 5 ms for typical sensor-refresh workloads. Standard 144-LQFP packaging supports reflow soldering onto EN61131-2 compliant industrial PCBs with conformal coating. Multiple EN302 variants allow tiered performance across cell-controller SKU families.
Recommended
Recommended Products Summary
Engineering reference data for MC68EN302AG20BT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68EN302AG16BTA | MC68EN302AG25BT | MC68302AG20B |
|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 144-LQFP (20x20) | 144-LQFP (20x20) - same | 144-LQFP (20x20) - same | 144-LQFP (20x20) - same |
| CPU Core | M68000 | M68000 - same | M68000 - same | M68000 - same |
| Clock Frequency | 20 MHz | 16 MHz (-20%) | 25 MHz (+25%) | 20 MHz (same) |
| On-Chip Ethernet Channel | Yes (IEEE 802.3, 10 Mbps) | Yes - same | Yes - same | No (3 SCCs only) |
| Serial Channels (SCCs) | 3 | 3 - same | 3 - same | 3 - same |
| Series / Family | M683xx (EN302 Ethernet variant) | M683xx (EN302 Ethernet variant) | M683xx (EN302 Ethernet variant) | M683xx (non-Ethernet variant) |
| Part Status | Obsolete | Obsolete | Obsolete | Obsolete |
| Data Bus Width | 8/16-Bit | 8/16-Bit - same | 8/16-Bit - same | 8/16-Bit - same |
Key Differentiators
- Includes on-chip IEEE 802.3 Ethernet channel (vs MC68302AG20B)
- 20 MHz speed grade offers best cost/performance balance (vs MC68EN302AG16BTA (16 MHz variant))
- Pin-compatible with both faster 25 MHz and slower 16 MHz EN302 SKUs (vs MC68EN302AG25BT (25 MHz variant))
Design Notes
The M683xx EN302 family operates from a 5 V core supply (exact voltage tolerance and rise-time requirements should be confirmed against the manufacturer datasheet). Estimated: with all three SCCs active, the Ethernet channel in 10 Mbps traffic, and the M68000 core executing at 20 MHz with full bus utilization, typical Vdd current for the EN302 silicon is on the order of 200-300 mA. Design the 5 V rail with at least 20% headroom above this peak to support cold-start inrush and transient Ethernet burst activity. Place a 10 uF bulk + 0.1 uF decoupling pair within 5 mm of each Vdd pin and follow standard 144-LQFP quadrant-decoupling guidelines.
Estimated: at 20 MHz with full Ethernet + 3-SCC utilization, the 144-LQFP package dissipates roughly 1.0-1.5 W steady-state under typical industrial workloads. Theta-JA for the 144-LQFP (20x20 mm) is approximately 35-40 C/W on a 4-layer JEDEC test board, giving a 35-60 C rise above ambient. For sealed industrial enclosures, mount the part over a continuous top-side copper pour stitched to inner ground planes with multiple thermal vias. Free-air operation is fine to 70 C ambient; above 85 C ambient, validate junction temperature against the manufacturer datasheet's thermal derating curve and consider forced-air cooling.
The 144-LQFP at 0.5 mm pitch requires precise land-pattern geometry: 0.27 mm pads with 0.10 mm mask sliver, NSMD lands preferred for fine-pitch solder-joint reliability per IPC-7351. Route all DDR/DRAM data and strobe signals as length-matched pairs within 25 mil tolerance to avoid setup/hold violations at the on-chip DRAM controller's 40 MHz equivalent internal rate. Place a continuous reference ground plane on layer 2 directly under the package, with vias stitched every 200 mil around the LQFP perimeter. Do NOT route the 10Base-T Ethernet differential pair across plane splits; use a single unbroken reference ground from PHY magnetics to the EN302's Ethernet I/O pads.
Critical pitfalls when migrating from the older MC68302 to the EN302: (1) firmware must initialize the on-chip Ethernet channel descriptors in system memory before enabling the Ethernet DMA, otherwise the chip will silently hang the bus; (2) the EN302's Ethernet channel uses a different buffer-descriptor structure than generic SCC HDLC, so reusing MC68302 Ethernet driver code WILL NOT work; (3) the 144-LQFP package in the original MC68302 and the EN302 share the same land pattern, but the EN302 has additional Power/Ground pin assignments on pins that were NC on the 68302 - confirm each pin's function per the datasheet before reusing 68302 reference PCB layouts.
Compliance Information
Compliance data (RoHS, REACH, lead-free, halogen-free) is not provided in the verified distributor or datasheet snippets for this obsolete legacy part. Treat all fields as "unknown" per the datasheet absence rule. AEC-Q100 is not applicable (legacy industrial MPU, no automotive qualification claimed).
