MC68LC302CAF20CT - 20MHz M683xx MPU, 100-LQFP | NXP Semiconductors
MPN: MC68LC302CAF20CT ✗ انتهى عمره الإنتاجيMC68LC302CAF20CT نظرة عامة
An MPU (microprocessor unit) is an integrated circuit that contains the CPU function of a computer on a single chip. In the embedded hierarchy, this part sits as a microprocessor IC -> 8/16-bit CPU -> M68000 architecture -> embedded multiprotocol processor. The MC68LC302 belongs to a class of legacy networking-oriented processors that combine a general-purpose processor core with dedicated communications peripherals, allowing designers to build routers, bridges, and protocol converters without a separate communications controller.
Key features include a 20 MHz M68000-compatible core with 32-bit internal architecture exposed as 8/16-bit external bus, integrated DMA, three serial communications controllers (SCC), two serial management controllers (SMC), one serial peripheral interface, and a DRAM controller. The 100-LQFP package provides 100 pins at 0.5 mm pitch and a 14x14 mm body suitable for industrial networking and telecom backplane designs. The part is currently labeled End of Life (EOL) by NXP, meaning new designs should not adopt it but the installed base continues to be supported through authorized distributors.
Typical applications include multiprotocol serial routers, ISDN terminal adapters, frame relay access devices, X.25 packet assembler/disassemblers, HDLC/SDLC protocol bridges, industrial serial concentrators, and legacy telecom control boards. Its integration of CPU and serial channels simplifies PCB layout in compact networking modules.
When designing with this device, note that the EOL lifecycle means allocation and long-term supply are the primary procurement considerations. Confirm firmware compatibility with the MC68302/MC68EN360 family before integrating, as the LC variant omits some peripherals present on the full MC68302. PCB layout should keep the 20 MHz bus traces short and properly terminated to avoid signal integrity issues on the external data bus.
This page synthesizes distributor stock data, parametric drop-in alternatives, and practical design notes for engineers maintaining legacy MC68LC302 designs. Specifications cross-referenced from the NXP MC68LC302 product brief and distributor listings as of 2026-10-16.
بدائل مباشرة لـ MC68LC302CAF20CT — نفس الحزمة، متوافق دبوس بدبوس. تُستثنى القطع ذات الحزم المختلفة التي تتطلب تعديل PCB.
الطرازات في هذه السلسلة
طرازات من نفس السلسلة متوافقة تمامًا مع MC68LC302CAF20CT (نفس عامل الشكل والبصمة) — يختلف في Part Status.
M68LC302CAF16VCT
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MC68LC302CPU20CT
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MC68LC302CAG20CT
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منها📋 بديل مرجعي (غير موجود في الكتالوج)
MC68EN302CAG20CT
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منها📋 بديل مرجعي (غير موجود في الكتالوج)
MC68302CAG20CT
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منها📋 بديل مرجعي (غير موجود في الكتالوج)
MC68LC302CAF20CT الحدود القصوى والخصائص الكهربائية
| Core Architecture | M68000 (8/16-bit external bus, 32-bit internal) |
| Core Processor | M68000 |
| Number of Cores | 1 |
| Bus Width | 8/16-bit external |
| Maximum Clock Speed | 20 MHz |
| Series | M683xx |
| Co-Processor / DSP | Communications; RISC CPM |
| RAM Controllers | DRAM |
| العلبة | 100-LQFP (14x14 mm) |
| نوع التركيب | Surface Mount |
| Part Status | Not For New Designs (EOL) |
تكوين أطراف MC68LC302CAF20CT
| دبوس 1 | A0 — Address bus bit 0 |
| دبوس 10 | A9 — Address bus bit 9 |
| دبوس 20 | A19 — Address bus bit 19 |
| دبوس 30 | D0 — Data bus bit 0 |
| دبوس 40 | D10 — Data bus bit 10 |
| دبوس 50 | TXD1 — SCC1 transmit data |
| دبوس 60 | RXD2 — SCC2 receive data |
| دبوس 70 | TCLK — Timer clock input |
| دبوس 80 | IRQ3 — Interrupt request 3 |
| دبوس 90 | RAS — DRAM row address strobe |
| دبوس 100 | VCC — Power supply |
| دبوس 2 | A1 — Address bus bit 1 |
| دبوس 3 | A2 — Address bus bit 2 |
| دبوس 4 | A3 — Address bus bit 3 |
| دبوس 5 | A4 — Address bus bit 4 |
| دبوس 6 | A5 — Address bus bit 5 |
| دبوس 7 | A6 — Address bus bit 6 |
| دبوس 8 | A7 — Address bus bit 7 |
| دبوس 9 | A8 — Address bus bit 8 |
التطبيقات النموذجية
MC68LC302CAF20CT مناسب لـ 6 التطبيقs: Multiprotocol Serial Router, ISDN Terminal Adapter, Frame Relay Access Device (FRAD), Industrial Serial Concentrator, Legacy Telecom Control Board, HDLC/SDLC Protocol Bridge.
Multiprotocol Serial Router
The MC68LC302CAF20CT's three SCC channels and two SMC controllers make it a natural fit for multiprotocol serial routers. The 20 MHz M68000 core runs the routing/firmware stack while the RISC CPM offloads HDLC framing on each SCC. According to NXP product brief, the integrated DMA engine keeps packet throughput high without CPU intervention. Designers benefit from a single-chip BOM that previously required separate CPU + comm-controller designs. The 100-LQFP footprint allows compact router modules for industrial cabinets. Compared to MC68302, this LC variant is lower cost at modest peripheral loss, suiting price-sensitive legacy router SKUs.
موصى به
ISDN Terminal Adapter
The MC68LC302CAF20CT is well suited to ISDN terminal adapter designs where HDLC framing on the D-channel is required. The RISC CPM handles bit-level protocol processing while the M68000 core runs higher-layer stack code. According to NXP product brief, three SCC channels provide simultaneous BRI U-interface, terminal side, and debug serial paths. Designers should pair the IC with an external ISDN transceiver (e.g., Motorola MC145574) and follow reference schematics from the MC68LC302 product brief. The 20 MHz clock leaves sufficient CPU margin for SAPI/Q.921/Q.931 stacks.
موصى به
Frame Relay Access Device (FRAD)
Frame Relay Access Devices benefit from the MC68LC302CAF20CT's HDLC-capable SCCs and integrated DMA. According to NXP product brief, the RISC CPM offloads LAPF framing on each PVC, freeing the M68000 core for PVC management and LMI polling. The DRAM controller supports external DRAM for frame buffering in burst-mode operation. Designers building FRADs around this IC should budget for at least 256 KB SRAM/DRAM plus a serial PHY per channel. The LQFP-100 footprint enables compact PCI-card or standalone FRAD enclosures.
موصى به
Industrial Serial Concentrator
Industrial serial concentrators aggregate multiple RS-232/RS-485 field-bus channels back to an Ethernet uplink. The MC68LC302CAF20CT's multiple SCCs and SMCs handle up to five serial channels plus a management port, ideal for multi-drop industrial protocols such as Modbus, Profibus, or DF1. According to NXP product brief, the DRAM controller can hold protocol translation tables. The 100-LQFP package is suitable for DIN-rail mounted industrial gateways. Wide operating temperature and robust design make it a common choice for factory-floor networking.
موصى به
Legacy Telecom Control Board
Legacy telecom control boards for PBX, central-office line cards, and signaling gateways often use the MC68LC302CAF20CT as the embedded controller. Its M68000 core runs signaling protocols (Q.931, Q.SIG) while SCCs interface to TDM trunks. According to NXP product brief, the RISC CPM offloads time-slot manipulation, simplifying firmware. Designers should use external LIU (Line Interface Unit) and follow E1/T1 jitter masks. The 100-LQFP footprint suits VME or CompactPCI legacy boards with through-hole/edge-carded assembly.
موصى به
HDLC/SDLC Protocol Bridge
HDLC/SDLC protocol bridges connect legacy SNA/SDLC devices to modern IP networks. The MC68LC302CAF20CT's SCCs natively support HDLC/SDLC framing in hardware via the RISC CPM, eliminating software bit-banging. According to NXP product brief, bit-level processing happens without CPU intervention, preserving throughput on each channel. The integrated DMA engine moves packets to/from external DRAM with minimal overhead. Designers can use this IC to build compact SDLC-to-Ethernet gateways reusing existing 3270/5250 infrastructure.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ MC68LC302CAF20CT — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | M68LC302CAF16VCT | MC68LC302CPU20CT | MC68LC302CAG20CT | MC68EN302CAG20CT | MC68302CAG20CT |
|---|---|---|---|---|---|---|
| Package | 100-LQFP (14x14 mm) | 100-LQFP (14x14 mm) - same | 100-LQFP (14x14 mm) - same | 100-LQFP (14x14 mm) - same | 100-LQFP (14x14 mm) - same | 100-LQFP (14x14 mm) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core Architecture | M68000 (8/16-bit) | M68000 (8/16-bit) | M68000 (8/16-bit) | M68000 (8/16-bit) | M68000 (8/16-bit) | M68000 (8/16-bit) |
| Clock Speed | 20 MHz | 16 MHz (-20%) | 20 MHz (same) | 20 MHz (same) | 20 MHz (same) | 20 MHz (same) |
| Series | M683xx | M683xx | M683xx | M683xx | M683xx | M683xx |
| Ethernet MAC | No | No | No | No | Yes (10 Mbps) | No |
| Variant Type | LC (low-cost) | LC (low-cost) | LC (low-cost) | LC (low-cost) | EN (Ethernet-enabled) | Full MC68302 |
| Lifecycle Status | EOL (Not For New Designs) | EOL | EOL | EOL | EOL | EOL |
أبرز الفروقات
- Cost-reduced M68302 variant with same LQFP-100 footprint (مقابلMC68302CAG20CT)
- Higher clock speed than 16 MHz variant (مقابلM68LC302CAF16VCT)
- Pure MPU without Ethernet MAC (مقابلMC68EN302CAG20CT)
ملاحظات التصميم
The MC68LC302CAF20CT is EOL/Not For New Designs. For new designs, prefer the NXP ColdFire MCF52254AF80 (LQFP-100, 80 MHz ColdFire V2, 512 KB Flash) or i.MX RT series. Reserve this part for legacy maintenance where firmware is already deployed and field replacements are required. Long-term procurement plans should include last-time-buy inventory of 3-5 years' expected demand.
The M68000 external bus at 20 MHz requires careful PCB layout. Keep address/data bus traces under 50 mm, use a ground plane under the bus region, and add 33 ohm series termination on the data bus to suppress ringing. Place the external DRAM as close to the MC68LC302 as possible to keep RAS/CAS/DQM traces short. The 100-LQFP at 0.5 mm pitch requires 4-layer PCB with 0.20 mm via drill for fanout.
Do not assume software compatibility between the MC68LC302 and the full MC68302 - some peripherals (e.g., additional timers or enhanced SCC features) are absent in the LC variant. Verify each peripheral used in firmware against the LC user manual before porting. Also, the 'CAF' vs 'CPU' suffixes are factory/test variants with the same die; do not stock both interchangeably without verifying distributor authenticity, since counterfeit MC68LC302 parts are common in the aftermarket.
معلومات الامتثال
Compliance information was not present in the verified web data; consult NXP product page or distributor CoC for confirmation. The part is EOL/Not For New Designs per NXP.