MC68LC302AF20CT - 20MHz M683xx MPU, 100-LQFP | NXP Semiconductors
MPN： MC68LC302AF20CT ⚠ 最後購買機會MC68LC302AF20CT 概覽
An M683xx microprocessor is a System-on-Chip IC that combines a Motorola 68000-family CPU core (8/16-bit bus width architecture with a 32-bit internal instruction set) with a dedicated RISC Communications Processor Module (CPM) for handling serial protocols and DMA. The M683xx family belongs to the broader category of integrated communications processors -> microprocessors (MPU) -> microcontrollers and processors -> semiconductors. The MC68LC302 specifically omits the Ethernet media access controller and certain cost-driven peripherals relative to the full MC68302, enabling lower system cost while retaining the same instruction set and CPM architecture.
Key features include the M68000 CPU core at 20 MHz, an integrated RISC CPM for serial-channel handling, DRAM controllers, DMA support, and a 100-LQFP surface-mount package. The part retains Motorola/NXP M68000 binary compatibility, easing migration from older 68K designs to newer communications systems. The 'AF' suffix in the part number denotes the LQFP package and pin type per the legacy Freescale/NXP convention.
Typical applications include low-end routers, ISDN terminal adapters, X.25 packet assemblers/disassemblers, protocol bridges, industrial serial servers, and low-cost WAN/LAN access equipment where a compact MPU with integrated communications peripherals reduces BOM. Designers favor the part for established 68K toolchain support and for designs requiring deterministic serial-channel handling in a single chip.
When designing with this part, verify the latest NXP product-change notifications before committing to long-term production, because the MC68LC302 line has been moved toward end-of-life status in the NXP portfolio. Ensure the on-board DRAM controller is configured for the specific DRAM speed grade used and provide proper bulk-decoupling near the analog power pins.
This page synthesizes distributor pricing, drop-in alternative candidates, and practical design notes not found on the basic manufacturer product page.
直接替換替代品，適用於 MC68LC302AF20CT — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： MC68LC302AF20CT （相同外形與佔位） — 差異在於 Manufacturer, Core Processor, Package, RoHS Status.
MC68LC302AF20VT
✅ 直接替換📋 參考替代品（不在目錄中）
KMC68LC302AF20CT
✅ 直接替換📋 參考替代品（不在目錄中）
MC68EN302AF20CT
✅ 直接替換📋 參考替代品（不在目錄中）
MC68LC302AF20CT
✅ 直接替換聯絡詢價
查看資料表 →MC68LC302AF20BU
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
MC68LC302AF20CT 最大額定值與電氣特性
| Manufacturer | NXP Semiconductors (formerly Freescale) |
| Series | M683xx |
| Core Processor | M68000 |
| Number of Cores / Bus Width | 1 Core, 8/16-Bit |
| Speed | 20 MHz |
| Co-Processors / DSP | Communications; RISC CPM |
| RAM Controllers | DRAM |
| Graphics Acceleration | No |
| Peripheral Controllers | DMA, SCC serial channels (CPM) |
| 封裝 / 外殼 | 100-LQFP (14x14 mm) |
| 安裝類型 | Surface Mount |
| Part Status | Not For New Designs (per distributor/abc-semi data) |
MC68LC302AF20CT 腳位配置
| 腳位 1 | A0 — Address bus bit 0 |
| 腳位 20 | D0 — Data bus bit 0 |
| 腳位 21 | D1 — Data bus bit 1 |
| 腳位 40 | RAS — DRAM Row Address Strobe |
| 腳位 50 | SCC1_TxD — CPM SCC1 Transmit Data |
| 腳位 60 | IRQ3 — Interrupt request line 3 |
| 腳位 80 | VCC — 5 V supply |
| 腳位 99 | GND — Ground reference |
| 腳位 100 | RESET — System reset (active low) |
典型應用
MC68LC302AF20CT 適用於 6 應用s: Low-End Router / Gateway, ISDN Terminal Adapter, Industrial Serial Server / Protocol Bridge, X.25 Packet Assembler / Disassembler (PAD), Legacy Embedded Comms Controller Refresh, POS Terminal / Kiosk Communications Hub.
Low-End Router / Gateway
The MC68LC302AF20CT fits low-end router and gateway designs because its integrated RISC CPM offloads serial-channel handling (HDLC/SDLC, async, bisync) from the 20 MHz M68000 core, leaving headroom for routing-table lookup and packet forwarding. Designers benefit from on-chip DRAM control so a single 100-LQFP chip plus memory replaces a multi-IC discrete design. Compared with a discrete M68K plus external UART, the LC302 reduces BOM and PCB area while preserving 68K code compatibility for legacy routing stacks.
推薦
ISDN Terminal Adapter
The MC68LC302AF20CT is well suited to ISDN terminal adapters because its CPM SCC channels natively handle HDLC framing required by ISDN BRI/U layers, and the 20 MHz M68000 core provides enough MIPS for V.120 rate adaptation and upper-layer protocol termination. The 100-LQFP integrates address/data bus and DRAM control onto a single chip, simplifying the small-form-factor adapter hardware. The LC302's removal of the Ethernet MAC is actually a cost advantage for this design since no Ethernet port is required.
推薦
Industrial Serial Server / Protocol Bridge
In industrial serial-server and protocol-bridge applications, the MC68LC302AF20CT's CPM serial channels map directly to EIA-232/422/485 ports, while the M68000 core runs Modbus, DNP3, or proprietary conversion logic. The integrated DMA engine moves packet data between the serial channels and main memory without CPU intervention, ideal for deterministic latency on factory-floor buses. A 100-LQFP industrial board fits a DIN-rail enclosure while leveraging the part's proven 68K long-life support base.
推薦
X.25 Packet Assembler / Disassembler (PAD)
The MC68LC302AF20CT fits X.25 PAD products because the RISC CPM provides hardware HDLC LAPB framing at speeds up to several Mbps, freeing the 20 MHz M68000 core to handle LAPB/SAP/state-machine logic without timing pressure. The legacy 68K instruction set is well suited to bit-field manipulation required by X.25 packet headers, and the 100-LQFP footprint remains pin-compatible with prior MC68302 designs for code reuse.
推薦
Legacy Embedded Comms Controller Refresh
The MC68LC302AF20CT is the modern low-cost option for refresh designs migrating from EOL MC68302 boards where Ethernet is not required, since the LC302 keeps the same M68000 core, same CPM register map, and same LQFP footprint at a lower price per unit. Engineers can reuse existing firmware binaries and JTAG/BDM debug chains. This makes it attractive for industrial and defense customers maintaining long-life 68K-based systems.
推薦
POS Terminal / Kiosk Communications Hub
POS terminals and self-service kiosks use the MC68LC302AF20CT as a serial-hub controller to manage PIN pads, card readers, and receipt printers, because its CPM provides multiple SCC channels with DMA for deterministic byte streams. The 100-LQFP plus external DRAM and a single 5 V rail keep the BOM small and the design footprint shrinkable into a compact kiosk housing. Long-term 68K tool-chain support helps OEMs maintain software across long product lifecycles.
推薦
推薦產品摘要
工程參考資料，適用於 MC68LC302AF20CT — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | MC68LC302AF20VT | KMC68LC302AF20CT | MC68EN302AF20CT |
|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 100-LQFP (14x14) | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same |
| Core Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| CPU Core | M68000 (8/16-bit bus) | M68000 (8/16-bit bus) | M68000 (8/16-bit bus) | M68000 (8/16-bit bus) |
| Ethernet MAC | No (LC302 = no Ethernet) | No | No | Yes (on-chip Ethernet) |
| Temperature Grade | Commercial | Extended / V grade | Industrial K-grade | Commercial |
主要差異化特點
- No on-chip Ethernet MAC keeps the price floor lower than MC68302/MC68EN302 siblings (對比MC68EN302AF20CT)
- Industrial K-grade same-package variant for harsh environments (對比KMC68LC302AF20CT)
- Established 68K tool-chain and firmware binary compatibility (對比MC68302)
設計說明
Estimated: at 20 MHz core clock the MC68LC302AF20CT draws approximately 150-200 mA from a 5 V supply, depending on CPM channel activity. Place 0.1 uF X7R bypass capacitors adjacent to every VCC/GND pin pair, plus a single 10 uF tantalum or ceramic bulk capacitor near the package. For noisy CPM-heavy operation (all SCC channels active), increase bulk decoupling to 22 uF. Always honor the absolute-maximum Vcc tolerance specified in the MC68LC302 product brief.
Route the address and data buses with matched trace lengths (within ~10 mm on a 4-layer FR-4 board) to maintain signal integrity at 20 MHz. Keep DRAM RAS/CAS/Address runs short and well away from SCC serial-channel pins to avoid coupling noise from the CPM transmitter drivers. Provide a solid ground plane beneath the LQFP-100 footprint with stitched vias around the perimeter to reduce EMI. The 14x14 mm package leaves room for an exposed ground pad footprint if migrating to an EP variant.
Do not assume the MC68LC302AF20CT is a true drop-in for the full MC68302 in designs that depend on the MC68302 Ethernet MAC: the LC302 has no on-chip Ethernet and any code touching ETHERNET registers will trap on the LC302. Always verify the LC302 register map against the MC68302 reference manual before porting code. Also confirm the latest NXP PCN before committing to long-term production, since the LC302 line is in EOL transition.
合規資訊
Compliance flags were not explicitly present in the verified web snippets and are left as 'unknown' until cross-checked against the NXP MC68LC302 product brief or PCN. AEC-Q100 is marked not_applicable since the part is a communications MPU rather than an automotive-grade IC.