MC68HC908LB8CPE - 8KB Flash 8-Bit HC08 MCU | Freescale | 20-DIP
N.º de pieza: MC68HC908LB8CPE ✗ Fin de vida| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $12.5 | $12,50 |
| 10 | $11.25 | $112,50 |
| 100 | $9.8 | $980,00 |
| 500 | $8.4 | $4.200,00 |
| 1.000 | $7.2 | $7.200,00 |
MC68HC908LB8CPE Descripción general
An 8-bit microcontroller is a single-chip computer built around an 8-bit data path and a Harvard or von Neumann architecture optimized for deterministic, low-power embedded control. Within the broader hierarchy, the MC68HC908LB8CPE belongs to the HC08 sub-family -> 8-bit MCU family -> microcontroller category -> embedded processor -> semiconductor. The HC08 architecture succeeded the HC05 with a FLASH-based program store, an enhanced instruction set including a multiply instruction, and improved peripherals, while retaining the legacy HC05 toolchain for migration. The 'LB8' suffix indicates a low-pin-count variant tailored for space-constrained human-interface and lighting-balast applications.
Key features include an internal 8MHz oscillator (trimmable for accuracy), 18 bidirectional I/O pins with programmable pull-ups, an enhanced serial communications interface (ESCI), a 16-bit timer with input-capture and PWM output channels, and a keyboard interrupt module for low-power wake-on-key. The on-chip FLASH supports byte-erase and block-erase operations over a typical endurance of 10,000 cycles, while 128 bytes of RAM back the C stack and data variables.
At the architecture level the MC68HC908LB8CPE uses a von Neumann bus with a 16-bit program counter, an 8-bit accumulator plus index register, and a hardware multiply (MUL) instruction that executes in 5 bus cycles - faster than software loops. The internal oscillator simplifies BOM by removing two crystal pads, and the FLASH controller supports in-circuit programming through the standard background debug mode (BDM) interface for in-system firmware updates.
Typical applications include dimmable fluorescent lamp ballasts, low-end household appliances such as washing-machine user-interface boards, fan and pump controllers, remote-control transmitters, and small industrial control panels. The 18 I/O pins are sufficient to drive a multiplexed keypad plus a 7-segment display without external expanders.
In a 20-DIP through-hole footprint the part supports hand-prototyping and socket replacement, which is convenient for legacy service and educational labs. Designers moving to surface mount should evaluate the MC68HC908LB8CFD (SOIC-20) or migrate forward to the MC9S08 family for a modern pin-compatible upgrade path with active production.
This page synthesizes distributor pricing, drop-in same-footprint alternatives, and practical engineering design notes not found in the manufacturer datasheet - useful for engineers maintaining legacy HC08 designs and qualifying second sources.
Alternativas directas para MC68HC908LB8CPE — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MC68HC908LB8CFD
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
MC68HC908LB8MPE
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
MC68HC908LB8CPE-R
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
MC68HC908JB8CPE
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
MC68HC908QT4CPE
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
MC68HC908LB8CPE Valores máximos y características eléctricas
| Family | HC08 (M68HC08) |
| Core | 8-bit HC08 CPU |
| Program Memory Type | FLASH |
| Program Memory Size | 8 KB (8K x 8) |
| RAM Size | 128 x 8 (128 bytes) |
| Frecuencia de reloj máxima | 8 MHz (internal oscillator) |
| Number of I/O | 18 |
| Encapsulado / Carcasa | 20-DIP (0.300 inch, 7.62 mm) |
| Tipo de montaje | Through-Hole |
| Oscillator Type | Internal |
| Peripherals | LVD, POR, enhanced SCI (ESCI), 16-bit timer, keyboard interrupt |
| Connectivity | SCI / UART |
| Nivel MSL | 1 (unsealed through-hole) |
| Instruction Set | HC08 (MUL, STOP, WAIT) |
Configuración de pines de MC68HC908LB8CPE
| Pin 1 | PTA0/KBD0 — Port A bit 0 / Keyboard interrupt 0 |
| Pin 2 | PTA1/KBD1 — Port A bit 1 / Keyboard interrupt 1 |
| Pin 3 | PTA2/KBD2 — Port A bit 2 / Keyboard interrupt 2 |
| Pin 4 | PTA3/KBD3 — Port A bit 3 / Keyboard interrupt 3 |
| Pin 5 | VDD — Positive supply voltage |
| Pin 6 | VSS — Ground reference |
| Pin 7 | PTA4/TACH — Port A bit 4 / Tachometer input timer |
| Pin 8 | PTA5/RESET — Port A bit 5 / Reset input (open-drain) |
| Pin 9 | PTA6/IRQ — Port A bit 6 / External IRQ input |
| Pin 10 | PTA7 — Port A bit 7 |
| Pin 11 | PTB0/TxD — Port B bit 0 / SCI transmit data |
| Pin 12 | PTB1/RxD — Port B bit 1 / SCI receive data |
| Pin 13 | PTB2 — Port B bit 2 |
| Pin 14 | PTB3 — Port B bit 3 |
| Pin 15 | PTB4/T1CH0 — Port B bit 4 / Timer1 channel 0 PWM |
| Pin 16 | PTB5/T1CH1 — Port B bit 5 / Timer1 channel 1 PWM |
| Pin 17 | PTB6 — Port B bit 6 |
| Pin 18 | PTB7 — Port B bit 7 |
| Pin 19 | PTC0 — Port C bit 0 |
| Pin 20 | PTC1/BDM — Port C bit 1 / Background debug mode |
Aplicaciones típicas
MC68HC908LB8CPE es adecuado para 6 aplicacións: Dimmable Fluorescent Lamp Ballast, Household Appliance User-Interface Board, Fan and Pump Speed Controller, Remote Control Transmitter, Industrial Control Panels (Legacy Drop-In), Educational Microcontroller Trainer Board.
Dimmable Fluorescent Lamp Ballast
The MC68HC908LB8CPE was purpose-designed for low-end dimmable fluorescent-lamp ballast control. With its 16-bit timer providing PWM output channels, the LB8 variant can drive gate-driver stages for IGBT or MOSFET half-bridge switching at the dimming frequency. The 18 I/O lines are sufficient to handle zero-crossing detect, lamp-current sensing, and filament-heating control loops without external I/O expanders. The internal 8MHz oscillator eliminates two crystal pads, reducing BOM and ballast board area. The 'LB8' suffix in the part number literally marks the lighting-ballast (LB) family. The integrated low-voltage detector (LVD) protects against brown-outs during lamp-startup transients - critical for ballast reliability.
Recomendado
Household Appliance User-Interface Board
In washing machines, dishwashers, and microwave ovens, the MC68HC908LB8CPE serves as the user-interface microcontroller for keypad scanning, 7-segment or LCD display driving, and buzzer/relay control. The keyboard-interrupt module wakes the part from STOP mode on key-press, enabling <10uA standby current - meeting ENERGY STAR idle-power budgets. The 18 I/O pins multiplex a 4x4 keypad plus 4-digit 7-segment display without external logic. FLASH-based firmware allows field re-flash via BDM when product variants require different feature sets.
Recomendado
Fan and Pump Speed Controller
Low-power BLDC fan and small DC pump controllers use the MC68HC908LB8CPE to read tachometer feedback and output PWM drive signals to the FET gate driver. The 16-bit timer counts tach pulses and triggers PWM compare-match updates at switching frequencies up to 50kHz. Internal oscillator accuracy is adequate for open-loop fan curves; for closed-loop PID control firmware can use the multiplier for fixed-point math. The HC08 STOP mode drops power to <1mA, useful when the fan is idle.
Recomendado
Remote Control Transmitter
Battery-powered IR/RF remote controls leverage the MC68HC908LB8CPE's keyboard-interrupt wake, ultra-low STOP-mode current, and on-chip FLASH for IR-protocol encoding (RC5, NEC, SIRC). The 8KB FLASH stores multiple protocol tables for universal-remote designs. The internal oscillator removes the need for a ceramic resonator, reducing BOM by ~$0.15. The 20-DIP footprint is acceptable in remote-control hand units where size is not extreme and battery contacts are large.
Recomendado
Industrial Control Panels (Legacy Drop-In)
Industrial control panels often need exact 20-DIP-form-factor MCUs to fit legacy PCB footprints when service-repairing older equipment. The MC68HC908LB8CPE matches this exact footprint and pinout. With 8KB FLASH, 128 bytes RAM, 18 I/O and the ESCI for RS-232/RS-485 bridge communications, it supports relay control, sensor readout, and HMI-link functions typical of PLC terminal blocks. Note that lead times may run 8-12 weeks; consider MC9S08 migration for new designs.
Recomendado
Educational Microcontroller Trainer Board
Through-hole 20-DIP parts like the MC68HC908LB8CPE remain popular in university microcontrollers courses because students can socket, swap, and probe each pin without microscope rework. The HC08 instruction set is small enough for a one-semester course, while the FLASH/BDM programming model teaches in-system firmware development. With 8KB FLASH the part hosts a real RTOS kernel or a non-trivial C application as a final project.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MC68HC908LB8CPE — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MC68HC908LB8CFD | MC68HC908LB8MPE | MC68HC908JB8CPE |
|---|---|---|---|---|
| Brand | NXP Semiconductors (Freescale) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 20-DIP (PDIP) | 20-SOIC (same die) | 20-DIP (same) | 20-DIP (same) |
| Program Memory | 8 KB FLASH | 8 KB FLASH | 8 KB FLASH | 8 KB FLASH |
| RAM | 128 bytes | 128 bytes | 128 bytes | 256 bytes |
| Max Clock Frequency | 8 MHz internal | 8 MHz internal | 8 MHz internal | 8 MHz internal |
| Number of I/O | 18 | 18 | 18 | 18 |
| USB Support | No | No | No | Yes (USB 1.1) |
| Family / Application | HC08 LB8 - Lighting Ballast | HC08 LB8 - Lighting Ballast | HC08 LB8 - Lighting Ballast | HC08 JB8 - USB Peripheral |
| Lifecycle Status | Obsolete (Rochester stock) | Obsolete | Obsolete | Obsolete |
Diferenciadores clave
- Lighting-Ballast-optimized part number suffix LB8 (frente a MC68HC908JB8CPE)
- 20-pin PDIP through-hole format for legacy compatibility (frente a MC68HC908LB8CFD)
- Internal oscillator - no external crystal required (frente a MC68HC908QT4CPE)
Notas de diseño
Estimated supply-voltage analysis. The HC08 LB family typically operates from 3V to 5.5V Vdd; for stable FLASH programming Vdd must remain above 4.5V. Brown-out during in-system programming can corrupt the FLASH array - always enable the LVD (low-voltage detect) module and the COP (computer operating properly) watchdog. When sourcing obsolete stock, prefer parts with date codes within the last 5 years; aged HC08 FLASH parts can show retention degradation if stored at high humidity.
Estimated dissipation. At 8MHz internal oscillator and 5V Vdd, the MC68HC908LB8CPE draws approximately 15mA active and <1mA in STOP mode. Through-hole 20-DIP packages have a thermal resistance around 60-80 C/W, so even at 15mA the junction rise is <1C - thermal management is rarely an issue. However in enclosed lamp-ballast enclosures with ambient >85C, check the operating temperature spec on the actual date-code lot to confirm compliance.
Estimated layout note. Place VDD bypass capacitors (100nF ceramic in parallel with 10uF electrolytic or tantalum) within 5mm of pin 5 (VDD) and pin 6 (VSS). For BDM programming access, expose pins 20 (BDM) and 8 (RESET) on a header or test pad. Avoid routing switching signals (timer PWM, SCI Tx/Rx) parallel to VDD traces for any length to prevent noise coupling into the analog LVD comparator. Keep the BDM wire under 100mm total length.
For battery-powered applications (remote controls, sensors), use STOP mode with keyboard-interrupt wake. Estimating: STOP current is ~1uA on the HC08 LB family, allowing years of standby on a CR2032 cell. Wake sources are configured via the KBI register; debounce must be handled in firmware or by the keyboard polling loop. Avoid WAIT mode if the ESCI baud-rate generator is needed - WAIT can be deeper than expected.
Información de cumplimiento
Original Freescale HC08 family was not typically offered as RoHS-compliant in PDIP form; consult Rochester Electronics (current authorized stock holder) for current RoHS status of MC68HC908LB8CPE lots. Not AEC-Q100 - this is a consumer/industrial MCU. Conflict-minerals compliance inherited from Freescale/NXP standard policy.
