MC68HC908LB8CDWE - 8-Bit 8MHz MCU 8KB Flash 20-SOIC | NXP
MPN： MC68HC908LB8CDWE ✗ 停產MC68HC908LB8CDWE 概覽
An 8-bit microcontroller (MCU) is a complete computing system on a single chip, combining a processor core, program memory, data memory, and peripherals. MCUs sit at the device level of the embedded-system hierarchy: microcontroller -> embedded processor -> semiconductor IC. The HC08 family is Freescale's enhanced successor to the classic 68HC05 architecture, object-code upward compatible and widely used in cost-sensitive embedded control.
Key features of the MC68HC908LB8CDWE include the HC08 CISC core executing at 8 MHz with efficient instruction throughput, 8KB in-system-programmable FLASH program memory eliminating masked-ROM lead times for low-volume designs, and 18 configurable I/O pins providing near-total pin utilization of the 20-pin package. On-chip LVR and POR circuits guarantee deterministic startup behavior during brown-out and power-up events without external supervisor ICs.
Technically, the part implements the HC08 core with 16-bit addressing, a stack pointer, and indexed addressing modes suited to C compilation. The FLASH memory supports field reprogramming, which simplifies firmware updates in serviced products. PWM capability supports lamp dimming, small motor drive, and buzzer tone generation directly from the MCU pins.
Typical applications include small appliance control, automotive body accessories, LED and lamp ballast control, and low-cost industrial sensing nodes where the PWM outputs and flash reprogrammability reduce system BOM count.
When designing with this MCU, note that the part is listed as obsolete: NXP no longer manufactures it, and current channel supply comes from remaining distribution stock and authorized aftermarket sources such as Rochester Electronics. New designs should target the MC9S08 or MC9S12 families.
This page synthesizes distributor pricing, lifecycle status, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a complete sourcing and design picture for this legacy 8-bit microcontroller.
直接替換替代品，適用於 MC68HC908LB8CDWE — 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： MC68HC908LB8CDWE （相同外形與佔位） — 差異在於 Package, Program Memory Size, RAM Size, Core Processor, Supply Voltage.
MC68HC908LB8VDWE
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
MC68HC908LB8MDWE
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →MC908QB8CDWE
✅ 直接替換聯絡詢價
查看資料表 →MC68HC908LB8CDWE 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 | 8KB (8K x 8) |
| Program Memory Type | FLASH |
| RAM Size | 128 x 8 |
| EEPROM Size | - |
| Number of I/O | 18 |
| Peripherals | LVR, POR, PWM |
| Connectivity | - |
| 封裝 | 20-SOIC (0.295 inch, 7.50 mm Width) |
| 安裝類型 | Surface Mount |
| Series | HC08 |
| Part Status | Obsolete |
MC68HC908LB8CDWE 20-soic (0.295 inch, 7.50 mm width) 腳位配置指南
MC68HC908LB8CDWE（20-soic (0.295 inch, 7.50 mm width) 封裝）的腳位配置。 此數位 IC 包含 GPIO、通訊介面（UART、SPI、I2C）與電源腳位。替代腳位功能與配置選項請參閱製造商資料表。對嵌入式系統設計與 PCB 佈局至關重要。
無詳細腳位定義資料： MC68HC908LB8CDWE.
請參閱 資料表 以查看完整腳位配置。
典型應用
MC68HC908LB8CDWE 適用於 6 應用s: Small Appliance Control, LED and Lamp Ballast Control, Automotive Body Accessories, Low-Cost Industrial Sensing Nodes, Battery-Powered Handheld Devices, Legacy Product Maintenance and Repair.
Small Appliance Control
The MC68HC908LB8CDWE fits small appliance control boards (blenders, coffee makers, fans) where its 18 I/O lines drive buttons, LEDs, relays, and buzzers directly from a single 20-SOIC chip. The integrated PWM peripheral generates tone or heater duty-cycle control without external timer ICs, while on-chip LVR and POR guarantee deterministic resets on unstable mains-derived supplies. Its 8KB FLASH supports in-system firmware updates during appliance service, cutting recall costs versus masked-ROM predecessors. At 8 MHz the HC08 core comfortably runs keypad scanning and state-machine control loops. Because the device is obsolete, appliance makers should secure aftermarket stock or migrate the footprint to the MC9S08 family.
推薦
LED and Lamp Ballast Control
Lamp ballast and LED driver boards benefit from the MC68HC908LB8CDWE's PWM output, which directly sets brightness or switching duty cycle from the MCU pin with no external PWM controller. The 20-SOIC package with 18 I/O accommodates dimming interfaces, fault feedback inputs, and relay or TRIAC drive signals in one chip. The Low-Voltage Reset module prevents undefined TRIAC gating during brown-out, an important safety consideration in mains-connected lighting. The 8KB FLASH allows field retuning of dimming curves after regulatory changes. Supply in the legacy HC08 line is constrained since the part is obsolete, so new ballast platforms should target MC9S08 equivalents while existing boards can use remaining stock.
推薦
Automotive Body Accessories
The MC68HC908LB8 family, including the extended-temperature V and M grades in the same 20-SOIC DW package, was widely used in automotive body-electronics modules such as mirror adjusters, seat memory, and lamp modules. The 18 I/O lines drive motors, lamps, and switches; PWM supports soft-start lamp dimming; and LVR/POR protect against crank-related supply dips during engine start. The 8KB FLASH allows end-of-line calibration data and firmware updates. Commercial-grade C-suffix parts are suitable only for cabin zones; the V grade (-40 to +85 C) covers under-hood-adjacent locations. Select the M-grade drop-in variant for harsher automotive thermal environments.
推薦
Low-Cost Industrial Sensing Nodes
Simple industrial sensors and limit-switch nodes use the MC68HC908LB8CDWE to condition inputs, debounce contacts, and drive 4-20 mA style outputs via PWM plus external filtering. The 8 MHz HC08 core handles averaging and thresholding routines within its 8KB FLASH and 128-byte RAM budget. LVR and POR provide safe power-up behavior in electrically noisy factory environments, while the surface-mount 20-SOIC withstands vibration better than DIP alternatives. FLASH programmability lets OEMs tune thresholds per installation without hardware changes. Given the obsolete status, integrators maintaining installed bases should qualify the aftermarket source or prepare a MC9S08-based footprint migration for future production runs.
推薦
Battery-Powered Handheld Devices
Handheld meters, remote controls, and portable instruments leverage the MC68HC908LB8CDWE's small 20-SOIC footprint and HC08 core efficiency to implement button scanning, display driving, and simple measurement sequencing from a compact BOM. The MCU's on-chip FLASH enables last-calibration-date storage and field firmware updates through a service fixture. The Low-Voltage Reset module prevents erratic behavior as the battery discharges toward the supply floor - a common failure mode in portable products. The 18 I/O lines directly drive segment displays and status LEDs without expansion logic. Verify the exact supply voltage floor against the datasheet before finalizing the battery chemistry and cutoff threshold in your design.
推薦
Legacy Product Maintenance and Repair
Service organizations repairing HC08-based legacy equipment use the MC68HC908LB8CDWE as a board-level replacement where masked ROM or OTP predecessors failed. Because the '908 flash part is firmware-compatible within the LB8 family and pin-identical across the C, V, and M temperature grades, technicians can substitute available grades within the same 20-SOIC footprint after confirming the operating environment temperature. The 8KB FLASH allows re-implementing or updating firmware dumped from surviving units, extending equipment life beyond OEM support. Sourcing relies on distribution remainders and the Rochester Electronics aftermarket; verify date codes and program each replacement before installation.
推薦
推薦產品摘要
工程參考資料，適用於 MC68HC908LB8CDWE — 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 | MC68HC908LB8VDWE | MC68HC908LB8MDWE | MC908QB8CDWE |
|---|---|---|---|---|
| Package | 20-SOIC (0.295 in, 7.50 mm Width) | 20-SOIC (7.50 mm Width) - same | 20-SOIC (7.50 mm Width) - same | 16-SOIC - different footprint |
| Brand | NXP Semiconductors (Freescale) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core | HC08, 8-Bit | HC08, 8-Bit | HC08, 8-Bit | HC08, 8-Bit |
| Clock Speed | 8 MHz | 8 MHz | 8 MHz | 8 MHz |
| Flash Memory | 8KB (8K x 8) | 8KB (8K x 8) | 8KB (8K x 8) | 8KB (8K x 8) |
| Operating Temperature | 0C to +70C (C grade) | -40C to +85C (V grade) | -40C to +125C class (M grade) | 0C to +70C (C grade) |
主要差異化特點
- Highest I/O density in its HC08 class (對比MC908QB8CDWE)
- Extended-temperature drop-in variants available in identical footprint (對比MC68HC908LB8MDWE)
- FLASH program memory instead of masked ROM (對比MC68HC705J1ACP)
設計說明
The MC68HC908LB8CDWE is obsolete. All supply now comes from residual distribution stock and the authorized aftermarket (Rochester Electronics lists it on DigiKey). Before committing a repair or bridge-production run, verify stock quantity, date codes, and whether parts are factory-new or reclaimed. Do not design new products around this MPN - NXP's supported successor path is the MC9S08 family, which requires firmware porting and typically a PCB footprint change.
Use the on-chip Low-Voltage Reset (LVR) and Power-On Reset (POR) as the primary reset mechanism, but confirm the actual Vcc operating range in the manufacturer datasheet before finalizing your supply rail and brown-out margin, since distributor listings did not publish this parameter. Decouple Vcc with a 0.1 uF ceramic capacitor placed within a few millimeters of the supply pin, plus bulk capacitance if driving relays or lamps from adjacent circuitry on the same rail.
The DW suffix denotes a wide-body 20-SOIC with 7.50 mm body width - confirm your land pattern is the wide SOIC (about 10.3 mm span) and not the narrow 3.9 mm SOIC used by 16-pin Q-family parts. Keep PWM output traces away from the oscillator and analog inputs to limit radiated and conducted coupling. With 18 of 20 pins as I/O, plan test points on unused configurations early, since rework access on 1.27 mm pitch SOIC pins is limited.
Monitor-mode FLASH programming requires specific pin conditions at reset entry; the exact entry procedure is documented in the M68HC08 family datasheet. When reprogramming parts in fixtures for legacy repairs, verify that your programmer still supports the HC08 monitor protocol - many modern programmers have dropped legacy HC08 support. Always blank-check flash parts before writing, as reclaimed aftermarket stock may contain prior-use firmware.
合規資訊
Compliance status was not published in the retrieved distributor data for this legacy part; original HC08-era production predates modern RoHS marking conventions in some date codes. Verify with the manufacturer or aftermarket supplier per date code.
