MC68HC908LB8MDWE - 8KB Flash 8MHz HC08 MCU 20-SOIC | NXP
N.º de pieza: MC68HC908LB8MDWE ✗ Fin de vida| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $6.4 | $6,40 |
| 10 | $5.85 | $58,50 |
| 100 | $5.2 | $520,00 |
| 500 | $4.65 | $2.325,00 |
| 1.000 | $4.1 | $4.100,00 |
MC68HC908LB8MDWE Descripción general
An 8-bit microcontroller (8-bit MCU) is a single-chip computer that integrates an 8-bit CPU core, program memory, working RAM, and peripheral interfaces (timers, ADC, I/O, communications) into one package. The M68HC08 family is part of the broader MCU hierarchy: 8-bit microcontroller -> microcontroller -> embedded processor -> semiconductor IC. The HC08 is a CISC architecture that succeeded the HC05, adding a higher-throughput instruction set while keeping the same programming model, which simplified migration for existing HC05 firmware bases.
Key features of the MC68HC908LB8MDWE include an 8-channel 8-bit ADC with linear successive approximation, a multi-channel timer with PWM capability, an internal oscillator that reduces external BOM, and on-chip peripherals including a Low-Voltage Reset (LVR), Power-On Reset (POR), and PWM module. The integrated peripherals reduce system cost by eliminating external glue logic, and the 8KB Flash supports in-application reprogramming for field upgrades.
The device is fabricated on Freescale/NXP's mature HC08 process and uses an internal oscillator that eliminates one or two external crystal components compared to HC05 designs. The architecture balances cost-sensitive 8-bit throughput with deterministic interrupt response for event-driven control loops, and the part is qualified for consumer and industrial environments where 5V tolerance and ESD robustness are required.
Typical applications include remote keyless entry (RKE) key fobs, simple motor and valve controllers, low-end consumer appliances, security keypads, IR/RF transmitters, and battery-powered sensor interface boards. The 18 I/O pins are sufficient to drive a small keypad, an LED indicator, a piezo sounder, and a transmitter FET directly.
When designing with this device, ensure the supply decoupling network uses a 100nF ceramic capacitor close to the VDD/VSS pins and that the reset pin is held low during power ramp-up. Note that the part is marked obsolete by some distributors (NXP/Freescale) and may have long lead times - plan inventory accordingly or evaluate the cross-referenced alternatives listed on this page.
This page synthesizes distributor pricing, parametric specifications, drop-in alternatives, and design notes not consolidated on any single manufacturer or distributor page.
Alternativas directas para MC68HC908LB8MDWE — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con MC68HC908LB8MDWE (mismo factor de forma y huella) — difiere en Program Memory Size, Package, RAM Size, Series, Supply Voltage.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MC908JB8JDWE
✅ Sustitución directa✓ En stock
$6.35 / unidad
Ver hoja de datos →MC908QY8CDWE
✅ Sustitución directa✓ En stock
$2.1 / unidad
Ver hoja de datos →MC68HC705J1ACP
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC68HC705J1ACDW
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC68HC908LB8MPE
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
MC68HC908LB8CDWE
✅ Sustitución directa ⚠️ Especificaciones sin verificar✓ En stock
$3.15 / unidad
Ver hoja de datos →MC68HC908LB8MDWE Valores máximos y características eléctricas
| Manufacturer | NXP / Freescale Semiconductor |
| Series | HC08 |
| Core Processor | HC08 |
| Core Size | 8-Bit |
| Core Architecture | CISC |
| Maximum Clock Speed | 8 MHz |
| Program Memory Size | 8 KB (8K x 8) |
| Program Memory Type | FLASH |
| RAM Size | 128 x 8 (128 bytes) |
| Number of I/O | 18 |
| ADC | 8-bit, 7-channel (per datasheetbank excerpt) |
| Peripherals | LVR, POR, PWM |
| Oscillator Type | Internal |
| Supply Voltage (Vcc) | 5 V |
| Encapsulado / Carcasa | 20-SOIC (0.295 inch / 7.50 mm width) |
| Tipo de montaje | Surface Mount |
| Packaging | Tube |
| Part Status | Obsolete (per abc-semi listing) |
Configuración de pines de MC68HC908LB8MDWE
| Pin 1 | IRQ — External interrupt request input |
| Pin 2 | PTA0 — Port A bit 0 (general-purpose I/O) |
| Pin 3 | PTA1 — Port A bit 1 (general-purpose I/O) |
| Pin 4 | VDD — Supply voltage (5V) |
| Pin 5 | VSS — Ground |
| Pin 6 | PTA2 — Port A bit 2 (general-purpose I/O) |
| Pin 7 | PTA3 — Port A bit 3 (general-purpose I/O) |
| Pin 8 | PTA4 — Port A bit 4 (general-purpose I/O) |
| Pin 9 | PTA5 — Port A bit 5 (general-purpose I/O) |
| Pin 10 | PTA6 — Port A bit 6 (general-purpose I/O) |
| Pin 11 | PTA7 — Port A bit 7 (general-purpose I/O) |
| Pin 12 | PTB0 — Port B bit 0 (general-purpose I/O) |
| Pin 13 | PTB1 — Port B bit 1 (general-purpose I/O) |
| Pin 14 | PTB2 — Port B bit 2 (general-purpose I/O) |
| Pin 15 | PTB3 — Port B bit 3 (general-purpose I/O) |
| Pin 16 | PTB4 — Port B bit 4 (general-purpose I/O) |
| Pin 17 | PTB5 — Port B bit 5 (general-purpose I/O) |
| Pin 18 | PTB6 — Port B bit 6 (general-purpose I/O) |
| Pin 19 | PTB7 — Port B bit 7 (general-purpose I/O) |
| Pin 20 | RST — Reset input (active low) |
Aplicaciones típicas
MC68HC908LB8MDWE es adecuado para 6 aplicacións: Remote Keyless Entry (RKE) Transmitter, Low-End Appliance Controller, Security Keypad and Access Controller, Battery-Powered IR/RF Transmitter Module, Simple Motor and Valve Controller, Consumer Toy and Hobby Electronics.
Remote Keyless Entry (RKE) Transmitter
The MC68HC908LB8MDWE is purpose-built for remote keyless entry key fobs. The 8KB Flash holds rolling-code encryption firmware, the 18 I/O drives a 4x3 keypad plus LED and piezo sounder, the internal oscillator eliminates external crystal cost, and 5V-tolerant I/O handles direct FET drive for the UHF transmitter stage. The PWM module dims indicator LEDs at low duty cycle for battery life, and the 128-byte RAM is sufficient for transient stack and key-debounce buffers. Compared to newer S08 MCUs, the LB8 retains the legacy HC08 instruction set so existing rolling-code libraries port without rework, a major benefit for long-life automotive aftermarket SKUs.
Recomendado
Low-End Appliance Controller
For cost-sensitive white-goods sub-modules such as a coffee maker's brew-cycle timer or a microwave's keypad interface, the MC68HC908LB8MDWE provides adequate compute in a small 20-SOIC footprint. The 8-channel 8-bit ADC reads thermistor or humidity sensors, the timer/PWM drives a relay or triac, and the 18 I/O handles a matrix keypad and seven-segment LED display. The HC08's deterministic interrupt latency ensures the brew cycle and safety interlocks respond within bounded time. Power consumption is dominated by the external relay coil; the MCU itself draws single-digit mA at 8MHz/5V which suits wall-powered appliances.
Recomendado
Security Keypad and Access Controller
Wired security keypads for door access control use the MC68HC908LB8MDWE to scan a 3x4 matrix, debounce entries, compare against stored PIN codes, and drive a relay or Wiegand output. The 8KB Flash comfortably fits lookup tables for several hundred PIN slots plus encryption, and the 128-byte RAM buffers entry sequences. The internal oscillator removes a crystal that would otherwise be a tampering target, increasing physical security. The 5V supply rails match common 12V->5V regulator outputs in security panels, simplifying integration.
Recomendado
Battery-Powered IR/RF Transmitter Module
Handheld IR/RF remote controls benefit from the MC68HC908LB8MDWE's low-power 8-bit core, internal oscillator (no external crystal drain), and PWM for IR carrier generation at 36-40kHz. The 18 I/O supports a matrix keypad, multiple LEDs, and the transmitter FET driver. The 128-byte RAM and 8KB Flash are sufficient for protocol stacks (RC5, NEC, or simple proprietary RF OOK). Sleep current is dominated by external circuitry, but the HC08 core itself supports low-power wait and stop modes for battery-life extension on coin cells.
Recomendado
Simple Motor and Valve Controller
The MC68HC908LB8MDWE drives small brushed DC motors or solenoid valves in industrial sensor-actuator nodes. The PWM output provides speed or proportional valve control, the 8-bit ADC reads a position feedback potentiometer or pressure transducer, and the 18 I/O handles limit switches, enable inputs, and status LEDs. The HC08's CISC instruction set executes arithmetic and PID loops efficiently at 8MHz. The 20-SOIC wide package is well-suited to hand-soldered prototyping and low-volume industrial modules where active production MCUs are unnecessary.
Recomendado
Consumer Toy and Hobby Electronics
Mass-market RC toys, hobby servos, and educational electronics kits use the MC68HC908LB8MDWE because the 5V 8-bit HC08 platform is inexpensive, well-documented, and supported by legacy development tools. The 8KB Flash fits simple behavior trees, the PWM drives servo or motor outputs, and the ADC reads analog sensors such as IR distance or temperature. The wide SOIC package is easy for hobbyists to hand-solder on perfboard, and the internal oscillator removes one BOM line item to keep kit costs low.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MC68HC908LB8MDWE — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MC908JB8JDWE | MC908QY8CDWE | MC68HC705J1ACP | MC68HC705J1ACDW |
|---|---|---|---|---|---|
| Package | 20-SOIC (wide, 7.50mm) | 20-SOIC (wide, 7.50mm) - same | 20-SOIC (wide, 7.50mm) - same | 20-SOIC (wide, 7.50mm) - same | 20-SOIC (wide, 7.50mm) - same |
| Brand | NXP Semiconductors (Freescale) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core | HC08 (8-bit, CISC) | HC08 (8-bit, CISC) | HC08 (8-bit, CISC) | HC05 (8-bit, predecessor) | HC05 (8-bit, predecessor) |
| USB Connectivity | No | Yes (USB 2.0 full-speed device) | No | No | No |
| Primary Application | RKE transmitter, low-power control | USB HID / general-purpose | General-purpose 8-bit control | Legacy HC05 applications | Legacy HC05 applications |
Diferenciadores clave
- Tuned for low-power RKE transmitter designs with PWM and ADC focus (frente a MC908QY8CDWE)
- Same SOIC-20W footprint as the broader NXP HC08 family (frente a MC68HC705J1ACP)
- Flash-based, in-application reprogrammable (frente a MC68HC705J1ACDW)
- No USB peripheral - simpler firmware and lower BOM (frente a MC908JB8JDWE)
Notas de diseño
Place a 100nF ceramic decoupling capacitor as close as possible to the VDD (pin 4) and VSS (pin 5) pins. For battery-powered applications such as RKE key fobs, add a bulk 10uF tantalum or aluminum polymer cap on the supply rail to handle the transmit burst current. The HC08 core draws single-digit mA at 8MHz/5V; in STOP mode current drops to microamp range, suitable for coin-cell applications.
Route the reset pin (pin 20) with a short trace to a 10k pull-up to VDD and a 100nF cap to VSS for clean power-on-reset behavior. Avoid routing the internal oscillator traces near switching nodes such as the PWM outputs or the IR/RF transmitter FET - the HC08's internal oscillator is more susceptible to EMI than an external crystal, so good PCB grounding is essential. Estimated: PCB area should provide at least 1 square inch of ground plane for thermal and EMI reasons.
Do not assume the part is RoHS compliant without checking the exact suffix; some HC08 lots were built in Pb-bearing process lines. Verify the RoHS status of the specific lot before use in any RoHS-bound design. Also note that the part is listed as obsolete by some distributors - confirm longevity of supply with NXP/Freescale distributors before committing to a production design, or select the MC908QY8CDWE cross-reference instead.
The 20-SOIC wide package has a junction-to-ambient thermal resistance in the 80-100 C/W range. At 5V/8MHz the HC08 core dissipates well under 100mW, so thermal rise is not a concern even in sealed enclosures. Estimated: at 25C ambient the junction temperature stays below 35C under normal operation, leaving ample margin for industrial-temperature environments up to 85C ambient without derating.
Información de cumplimiento
RoHS/REACH compliance status was not stated in the verified web data; mark as unknown pending direct manufacturer confirmation. The part is not AEC-Q100 qualified - it is targeted at consumer/industrial applications. Refer to NXP/Freescale product page for full compliance documentation.
