MC68HC908QT4CDW - 8-bit HC08 MCU 4KB Flash 8MHz | NXP
MPN： MC68HC908QT4CDW ✗ 停產MC68HC908QT4CDW 概覽
An 8-bit microcontroller (MCU) is a compact, self-contained computing element that integrates a CPU, program memory, RAM, peripherals, and I/O into a single chip. The MC68HC908QT4CDW belongs to the HC08 family — a CISC, Von Neumann architecture family of low-cost, high-performance 8-bit microcontrollers. Within the broader taxonomy, this device sits at: microcontroller -> 8-bit MCU -> HC08 family -> QY/QT sub-family -> embedded system component.
Key features include on-chip LVD (Low-Voltage Detect) and POR (Power-On Reset) peripherals, PWM output, internal oscillator (eliminating external crystal), and 4KB of in-system programmable Flash. The HC08 core uses an enhanced M68HC08 central processor with a von Neumann architecture. With 5 I/O pins available, the QT4 variant targets space-constrained applications where minimal pin count is essential.
Typical applications include low-cost consumer electronics, white goods control, automotive body electronics (non-safety), small appliances, simple sensor interfaces, and cost-sensitive industrial control. The 5V supply range suits traditional 5V system designs while the industrial temperature grade enables harsh-environment deployments.
When designing with this part, note that with only 5 I/O pins available, applications must rely heavily on peripheral functions (PWM, timers) and may need I/O expanders if more pins are required. Programming requires a compatible HC08 programmer/debugger interface. This page synthesizes distributor pricing, drop-in same-family alternatives, and practical design notes not found in the standalone datasheet.
直接替換替代品，適用於 MC68HC908QT4CDW — 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： MC68HC908QT4CDW （相同外形與佔位） — 差異在於 RAM Size, Number of I/O Pins, Peripherals, Program Memory Size, ADC.
MC68HC908QT2CDW
✅ 直接替換聯絡詢價
查看資料表 →MC68HC908QT1CDW
✅ 直接替換📋 參考替代品（不在目錄中）
MC68HC908QY4CDWE
✅ 直接替換📋 參考替代品（不在目錄中）
MCHC908QT4MDWE
✅ 直接替換聯絡詢價
查看資料表 →MC68HC908QY2CDWE
✅ 直接替換📋 參考替代品（不在目錄中）
MC68HC908QT4CDW 最大額定值與電氣特性
| Core Processor | HC08 |
| Core Size | 8-bit |
| Maximum Clock Speed | 8 MHz |
| Program Memory Size | 4 KB (4K x 8) Flash |
| RAM Size | 128 x 8 bytes |
| Number of I/O Pins | 5 |
| Supply Voltage (Vcc/Vdd) | 5 V (typical) |
| Oscillator Type | Internal |
| Peripherals | LVD, POR, PWM |
| 封裝 / 外殼 | 8-SOIC (0.209 inch / 5.30 mm width) |
| 安裝類型 | Surface Mount |
| 工作溫度 | -40C to +85C (Industrial) |
| RoHS 狀態 | unknown |
| Packaging | Tube |
MC68HC908QT4CDW 腳位配置
| 腳位 1 | PTA4/TCLK2/SS — I/O port A bit 4 / Timer clock / SPI SS (function multiplexed) |
| 腳位 2 | PTA3/ADC3 — I/O port A bit 3 / ADC channel 3 (multiplexed) |
| 腳位 3 | Vdd — Positive supply voltage (5 V typical) |
| 腳位 4 | Vss — Ground reference |
| 腳位 5 | PTA0/IRQ — I/O port A bit 0 / External interrupt request (multiplexed) |
| 腳位 6 | PTA1/ADC1 — I/O port A bit 1 / ADC channel 1 (multiplexed) |
| 腳位 7 | PTA2/ADC2 — I/O port A bit 2 / ADC channel 2 (multiplexed) |
| 腳位 8 | RST — Reset input (active low) |
典型應用
MC68HC908QT4CDW 適用於 6 應用s: Low-cost consumer electronics controller, White goods and small appliance control, Simple sensor interface modules, Automotive body electronics (non-safety), Industrial control and timing modules, Educational and hobbyist embedded projects.
Low-cost consumer electronics controller
The MC68HC908QT4CDW fits low-cost consumer electronics controllers because its 4 KB Flash, 128 B RAM, and 5 GPIO are sufficient for simple button/switch interfaces with PWM-driven LED or buzzer outputs. Operating at 5 V from a USB or wall-adapter-derived rail, it removes the need for an external crystal via its 8 MHz internal oscillator. The 8-SOIC package enables placement on single-sided PCBs to minimize BOM and assembly cost in high-volume products.
推薦
White goods and small appliance control
For washing machine sub-modules, microwave user interfaces, and small appliance controllers, the MC68HC908QT4CDW's industrial temperature grade (-40C to +85C), integrated LVD/POR, and PWM peripherals provide robust operation across mains-ripple environments. The 5 V supply domain suits relay and triac-driver interfaces commonly used in appliance designs. With 4 KB Flash, designers can implement timed-control state machines plus a simple UI driver without external memory.
推薦
Simple sensor interface modules
Sensor interface modules — temperature probes, optical switches, single-channel detectors — fit the MC68HC908QT4CDW's 5 I/O and PWM profile. The internal oscillator simplifies integration into compact PCB modules where board area is constrained. Industrial-grade operation supports factory floor installation, and the Flash-based program memory supports field firmware updates via HC08 MON08-compatible tools.
推薦
Automotive body electronics (non-safety)
Non-safety automotive body electronics — interior lighting controllers, simple door-module sub-tasks, accessory timers — historically used the MC68HC908QT4CDW. With 5 V supply tolerance and integrated LVD, it survives automotive cranking transients when paired with proper supply conditioning. The part is obsolete; for new designs use the AEC-Q100-qualified MCHC908QT4MDWE automotive variant as the drop-in pin-compatible upgrade.
推薦
Industrial control and timing modules
Industrial timing, sequencing, and simple control tasks that do not need networking fit the MC68HC908QT4CDW's resource profile. The PWM output can drive opto-isolators, small solenoids, or LED indicators directly, while the internal 8 MHz oscillator eliminates crystal failure modes common in vibrating industrial cabinets. Industrial temperature grade operation supports factory-floor deployment in cabinets and control panels.
推薦
Educational and hobbyist embedded projects
The MC68HC908QT4CDW is widely adopted in educational and hobbyist embedded projects because of its simple 8-SOIC footprint, exposed HC08 architecture, and rich legacy teaching material. It can be hand-soldered easily, programmed via low-cost MON08-compatible debuggers, and integrated into simple line-following robots, blinking-LED trainers, and timing experiments. The 4 KB Flash provides headroom for student projects while keeping complexity manageable.
推薦
推薦產品摘要
工程參考資料，適用於 MC68HC908QT4CDW — 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 | MC68HC908QT2CDW | MC68HC908QT1CDW | MC68HC908QY4CDWE | MCHC908QT4MDWE | MC68HC908QY2CDWE |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 8-SOIC | 8-SOIC - same | 8-SOIC - same | 8-SOIC (extended pinout) - same family | 8-SOIC - same | 8-SOIC (extended pinout) - same family |
| Program Memory (Flash) | 4 KB | 2 KB (-50%) | 1 KB (-75%) | 4 KB (same) | 4 KB (same) | 2 KB (-50%) |
| RAM Size | 128 bytes | 128 bytes (same) | 128 bytes (same) | 128 bytes (same) | 128 bytes (same) | 128 bytes (same) |
| Number of I/O | 5 | 5 (same) | 5 (same) | 13 (+160%) | 5 (same) | 13 (+160%) |
| Core Speed | 8 MHz | 8 MHz (same) | 8 MHz (same) | 8 MHz (same) | 8 MHz (same) | 8 MHz (same) |
| Oscillator Type | Internal | Internal | Internal | Internal | Internal | Internal |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +125C (Automotive/AEC-Q100) | -40C to +85C (Industrial) |
主要差異化特點
- Larger Flash within same 8-SOIC footprint (對比MC68HC908QT2CDW)
- Pin-compatible automotive grade option exists (對比MCHC908QT4MDWE)
- Minimal pin count optimized for cost-sensitive designs (對比MC68HC908QY4CDWE)
設計說明
Estimated: At 5 V Vdd and 8 MHz CPU clock with all 5 I/O toggling, typical active current is in the single-digit mA range. Add bulk decoupling (10 uF) near Vdd (pin 3) and a 100 nF ceramic between Vdd and Vss (pin 4) within 5 mm of the package to suppress switching transients. The integrated POR holds the device in reset until Vdd stabilizes, but ensure ramp time meets the datasheet specification.
Because the QT4 only exposes 5 I/O pins (PTA0-PTA4), several functions are multiplexed: PTA4/TCLK2/SS, PTA3/ADC3, PTA1/ADC1, PTA2/ADC2, PTA0/IRQ. Carefully plan pin allocation before layout; losing pins to peripherals can leave no general-purpose I/O available. Confirm the exact multiplex map in the HC08Q datasheet before finalizing the schematic to avoid I/O starvation on the smallest variant.
Estimated: At 5 V supply and 8 MHz, the 8-SOIC package dissipates well under 100 mW even at full activity. The industrial temperature grade (-40C to +85C) is the binding constraint; for environments up to +125C use the MCHC908QT4MDWE automotive drop-in instead. Standard SO-8 land patterns provide adequate copper for thermal relief in normal convection cooling.
合規資訊
Compliance data not present in the verified web data extract. RoHS/REACH status should be confirmed at the orderable distributor level. AEC-Q100 qualification applies only to the automotive MCHC908QT4MDWE variant, not the standard QT4.
