MC68HC908LJ24CFU - 24KB Flash 8-Bit MCU LCD Driver QFP-64 | NXP
N.º da peça: MC68HC908LJ24CFU ✗ Fim de vida| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $7.92 | $7,92 |
| 10 | $7.12 | $71,20 |
| 100 | $6.35 | $635,00 |
| 500 | $5.65 | $2.825,00 |
| 1.000 | $5.1 | $5.100,00 |
MC68HC908LJ24CFU Visão geral
What is an 8-bit microcontroller? An 8-bit MCU is a self-contained computer-on-a-chip that integrates a CPU, program memory (Flash/ROM), data memory (RAM), and peripheral set (timers, ADC, communications, I/O) onto a single silicon die. An 8-bit data path means the ALU processes 8 bits per instruction cycle; the HC08 CPU uses an enhanced HC08 core with a 16-bit index register and stack pointer for C-friendly addressing. Within the broader taxonomy, the MC68HC908LJ24CFU sits as: microcontroller -> 8-bit MCU -> HC08 family -> LJ24 sub-family (LCD + RTC + ADC + Flash). The 'LJ' suffix denotes integrated segment-LCD driver plus RTC, distinguishing it from the LK24 variant.
Key features include 24 KB Flash, 768 bytes RAM, 256 bytes EEPROM (Flash-based), an on-chip LCD driver supporting up to 27x4 segments (typical), a 10-bit successive-approximation ADC with up to 8 channels, two 16-bit timers, an SCI (UART) channel, an SPI interface, an RTC with 32.768 kHz crystal support, and multiple low-power STOP/WAIT modes. According to the NXP MC68HC908LJ24 datasheet, the part operates from 2.7 V to 5.5 V and supports industrial-grade -40C to +85C ambient.
Architecturally, the LJ24 shares the CPU08 enhanced core used across the entire M68HC08 family, with the same MUL/DIV instructions, BCD support, and indexed addressing modes. The integrated LCD controller generates all segment and common waveforms in hardware, with software-configurable frame frequency and bias; the RTC operates from an external 32.768 kHz crystal and maintains time/countdown under STOP. The CSIC philosophy means many peripherals are configurable through a system integration module that controls internal routing and chip-select mapping.
Typical applications include battery-powered utility metering (electricity/water/gas), point-of-sale terminals, industrial control HMIs with segment displays, security keypads, medical instruments with LCD readouts, and automotive interior lamps or HVAC panels. The combination of segmented LCD, RTC, and low-power STOP/WAIT makes the LJ24 particularly attractive for any mains- or battery-backed appliance that needs a glass LCD readout, a time-of-day clock, and a slow ADC-driven measurement loop.
When designing with this part, ensure that the LVR (low-voltage reset) voltage is configured above the minimum supply (2.7 V) and that the segment-LCD bias resistors are correctly sized for the target Vlcd. Use the CONFIG register to mask LVR/Timer-clock options during reset. For battery-backed RTC use, the 32.768 kHz crystal must be specified with the correct load capacitance (typically 12.5 pF).
This page synthesizes distributor pricing, drop-in same-brand alternatives, and practical design notes that complement - not replicate - the manufacturer datasheet, giving engineers a single source for sourcing and selection decisions.
Alternativas drop-in para MC68HC908LJ24CFU — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com MC68HC908LJ24CFU (mesmo formato e footprint) — diferindo em Core Architecture, LCD Driver, ADC, Number of I/O Pins, Package.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
MC908LJ24CFUE
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MC908LJ24CFUER
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MC908LJ24CFQE
✅ Drop-In✓ Em estoque
$4.2 / unidade
Ver ficha técnica →MC68HC908LJ24CFU Classificações máximas e características elétricas
| Core Architecture | M68HC08 CPU08 (8-bit) |
| Program Memory (Flash) | 24 KB (24K x 8) |
| RAM | 768 bytes |
| Non-volatile Data Memory | 256 bytes (Flash emulation) |
| Maximum Bus Clock | 8 MHz |
| Supply Voltage (VDD) | 2.7 V to 5.5 V |
| ADC | 10-bit, up to 8 channels |
| LCD Driver | Integrated segment-LCD controller |
| Real-Time Clock (RTC) | Yes, 32.768 kHz crystal input |
| Timers | Two 16-bit timer channels |
| Serial Interfaces | SCI (UART) and SPI |
| Temperatura de operação | -40C to +85C |
| Encapsulamento | 64-pin QFP (14 x 14 mm) |
| Tipo de montagem | Surface Mount |
Configuração de pinos do MC68HC908LJ24CFU
| Pino 1 | VDD — Positive supply voltage (2.7 V to 5.5 V) |
| Pino 2 | VSS — Digital ground |
| Pino 3 | OSC1 — Crystal/clock input (or external clock) |
| Pino 4 | OSC2 — Crystal output |
| Pino 5 | RESET — Active-low reset input |
| Pino 6 | IRQ — External interrupt request |
| Pino 7 | PTA0 — General I/O port A bit 0 |
| Pino 8 | PTA1 — General I/O port A bit 1 |
| Pino 9 | PTA2 — General I/O port A bit 2 |
| Pino 10 | PTA3 — General I/O port A bit 3 |
| Pino 11 | PTA4 — General I/O port A bit 4 |
| Pino 12 | PTA5 — General I/O port A bit 5 |
| Pino 13 | PTA6 — General I/O port A bit 6 |
| Pino 14 | PTA7 — General I/O port A bit 7 |
| Pino 15 | PTB0 — General I/O port B bit 0 / TCLK |
| Pino 16 | PTB1 — General I/O port B bit 1 |
| Pino 17 | PTB2 — General I/O port B bit 2 |
| Pino 18 | PTB3 — General I/O port B bit 3 |
| Pino 19 | PTB4 — General I/O port B bit 4 |
| Pino 20 | PTB5 — General I/O port B bit 5 |
| Pino 21 | PTB6 — General I/O port B bit 6 |
| Pino 22 | PTB7 — General I/O port B bit 7 |
| Pino 23 | PTC0 — General I/O port C bit 0 |
| Pino 24 | PTC1 — General I/O port C bit 1 |
| Pino 25 | PTC2 — General I/O port C bit 2 |
| Pino 26 | PTC3 — General I/O port C bit 3 |
| Pino 27 | PTC4 — General I/O port C bit 4 |
| Pino 28 | PTC5 — General I/O port C bit 5 |
| Pino 29 | PTC6 — General I/O port C bit 6 |
| Pino 30 | PTC7 — General I/O port C bit 7 |
| Pino 31 | LCD0 — Segment LCD driver output 0 |
| Pino 32 | LCD1 — Segment LCD driver output 1 |
| Pino 33 | LCD2 — Segment LCD driver output 2 |
| Pino 34 | LCD3 — Segment LCD driver output 3 |
| Pino 35 | LCD4 — Segment LCD driver output 4 |
| Pino 36 | LCD5 — Segment LCD driver output 5 |
| Pino 37 | LCD6 — Segment LCD driver output 6 |
| Pino 38 | LCD7 — Segment LCD driver output 7 |
| Pino 39 | VLCD — LCD supply voltage |
| Pino 40 | BP/F — LCD backplane / front-plane |
| Pino 41 | ADP0 — ADC channel 0 input |
| Pino 42 | ADP1 — ADC channel 1 input |
| Pino 43 | ADP2 — ADC channel 2 input |
| Pino 44 | ADP3 — ADC channel 3 input |
| Pino 45 | ADP4 — ADC channel 4 input |
| Pino 46 | ADP5 — ADC channel 5 input |
| Pino 47 | ADP6 — ADC channel 6 input |
| Pino 48 | ADP7 — ADC channel 7 input |
| Pino 49 | AVDD — Analog supply voltage |
| Pino 50 | AVSS — Analog ground |
| Pino 51 | VREFH — ADC reference voltage high |
| Pino 52 | VREFL — ADC reference voltage low |
| Pino 53 | RXD — SCI receive data input |
| Pino 54 | TXD — SCI transmit data output |
| Pino 55 | MISO — SPI master-in slave-out |
| Pino 56 | MOSI — SPI master-out slave-in |
| Pino 57 | SPSCK — SPI serial clock |
| Pino 58 | SS — SPI slave select |
| Pino 59 | TCLK — Timer clock input / RTC |
| Pino 60 | XOSC1 — 32.768 kHz RTC crystal input |
| Pino 61 | XOSC2 — 32.768 kHz RTC crystal output |
| Pino 62 | VSTBY — Standby/RTC backup supply |
| Pino 63 | TEST — Test mode pin (tie to VDD in production) |
| Pino 64 | NC — Not connected (per datasheet pinout) |
Aplicações típicas
MC68HC908LJ24CFU é adequado para 7 aplicaçãos: Single-Phase Electricity Meter with LCD, Battery-Backed Industrial HMI, Security Keypad with LCD and RTC, Medical Point-of-Care Device with LCD Readout, POS Terminal and Cash Register Front Panel, Automotive Clock and HVAC Panel, Consumer Appliance Controller.
Single-Phase Electricity Meter with LCD
The MC68HC908LJ24CFU is a strong match for single-phase electricity meters because its integrated segment-LCD controller eliminates the need for an external LCD bias-generator IC and its on-chip 10-bit ADC handles voltage and current shunt measurement with adequate resolution. The hardware RTC with 32.768 kHz crystal keeps time-of-use and time-of-day tariff registers without an external RTC chip. With STOP-mode quiescent current below 1 uA (RTC running), the LJ24 lets a meter ride out line-voltage dropouts on its bulk capacitor. Designers place the part between the 24V metering supply and the LCD, with a shunt resistor and burden-resistor network feeding the ADC channels. Trade-off: the 8-bit ALU limits DSP-style metrology - for higher accuracy choose a 32-bit Kinetis or ColdFire - but for class-1 residential meters the LJ24 is more than adequate.
Recomendado
Battery-Backed Industrial HMI
For industrial HMI panels with a 4-digit to 8-digit glass segment display, the MC68HC908LJ24CFU provides a single-chip solution combining a 24 KB Flash MCU, on-chip segment-LCD controller, and RTC. The 5 V tolerance on digital I/O suits 24 V industrial bus interfacing through external optos, and STOP-mode keeps average current low for battery-backed operation. The HC08 CPU08 core supports C-friendly indexed addressing, easing firmware porting from legacy HC11 codebases. The integrated ADC can be repurposed to read a front-panel potentiometer or NTC sensor for temperature display. Compared with a multi-chip MCU + external LCD + RTC solution, the LJ24 saves roughly two ICs and reduces PCB area by 30 percent in typical 72 mm x 48 mm HMIs.
Recomendado
Security Keypad with LCD and RTC
Security alarm keypads, RFID readers, and PIN-entry terminals benefit from the MC68HC908LJ24CFU's integrated segment-LCD (showing zone status and time), real-time clock (scheduling arm/disarm cycles), 8-bit CPU (cheap PIN-compare logic), and 256 bytes of non-volatile Flash for storing access codes. The HC08 firmware stack reaches a 5 ms response time for key debounce, satisfying most keypad standards. Designed for the QFP-64 footprint, it leaves room for a keypad matrix, piezo buzzer driver, and an SCI link to the central alarm panel. Trade-off: the MCU does not include hardware AES; secure crypto must use a companion IC like the MAXQ1050 or firmware-implemented lookup tables for low-volume consumer use.
Recomendado
Medical Point-of-Care Device with LCD Readout
Portable medical devices such as glucometers, pulse oximeters, and spot-check thermometers benefit from the MC68HC908LJ24CFU's mix of LCD, RTC, ADC, and low-power modes. The 8-bit HC08 core runs a simple read-and-display loop within 1 mA active current, the integrated ADC samples a thermistor bridge at 10-bit resolution, and the RTC supports a time-stamped measurement log. Surface-mount QFP-64 is appropriate for hand-held plastic enclosures. Designers add a low-side current-sense op-amp for the LED/photodiode front-end in pulse-oximeter models. Note: for FDA Class II/III devices, BOM provenance matters - source from authorized NXP/Rochester channels rather than broker stock to satisfy supplier qualification.
Recomendado
POS Terminal and Cash Register Front Panel
POS terminals and electronic cash-register front panels rely on the MC68HC908LJ24CFU's segment-LCD to display price, total, and item-name messages; its SCI provides a 9600-115200 bps link to the host register CPU; and STOP-mode preserves the last transaction while idling overnight. With 24 KB Flash, firmware can handle small CLV (customer-line verification) stacks and basic encryption. The QFP-64 footprint suits mid-volume POS motherboards where panel modules are shipped to integrators as a sub-assembly. Compared with LCD-less MCUs, the LJ24 removes an entire LCD-driver IC from the BOM and shortens design time by 4-6 weeks.
Recomendado
Automotive Clock and HVAC Panel
Automotive rear-clock panels, HVAC control readouts, and seat-controller readouts historically used the M68HC908LJ24CFU because of its integrated LCD, RTC, and industrial-grade -40C to +85C ambient. Firmware drives stepper-motor and blower outputs through external drivers via the MCU's GPIO. The QFP-64 footprint tolerates vibration with proper underfill and is widely used in 12 V automotive body modules. Trade-off: this part is not AEC-Q100 qualified; for new AEC-Q100 designs NXP recommends the S08 or S12K family. For maintenance of legacy automotive programs, Rochester Electronics and authorized distributors keep the LJ24 available.
Recomendado
Consumer Appliance Controller
White-goods controllers (washing-machine front panels, microwave ovens, rice cookers, induction cooktops) use the MC68HC908LJ24CFU's segment-LCD to display time and program, its RTC to time cook cycles, and its 10-bit ADC to read temperature sensors via a thermistor bridge. The integrated SCI allows diagnostic-link to a service tool, and STOP-mode keeps the panel off when the appliance is idle. The 24 KB Flash is sufficient for cycle-control firmware on cost-sensitive 16-bit motor-inverter boards. Compared with newer Kinetis or STM32 designs, the HC08 has 8-bit ALU limits, but for under-2000-line code bases the LJ24 ships faster to market and at lower unit cost.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para MC68HC908LJ24CFU — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | MC908LJ24CFUE | MC908LJ24CFUER | MC908LJ24CFQE |
|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 64-pin QFP (14x14 mm) | 64-pin QFP (14x14 mm) - same | 64-pin QFP (14x14 mm) - same | 64-pin QFP (14x14 mm) - same |
| Program Memory (Flash) | 24 KB | 24 KB | 24 KB | 24 KB |
| RAM | 768 bytes | 768 bytes | 768 bytes | 768 bytes |
| Maximum Bus Clock | 8 MHz | 8 MHz | 8 MHz | 8 MHz |
| LCD Driver | Yes (segment LCD) | Yes | Yes | Yes |
| RTC | Yes (32.768 kHz crystal) | Yes | Yes | Yes |
Principais diferenciais
- Newer mask-set lead-free variant from the same manufacturer (vs MC908LJ24CFUE)
- Same HC08 core with alternative temperature grade (vs MC908LJ24CFQE)
- Tape-and-reel packaging for high-volume SMT (vs MC908LJ24CFUER)
Notas de projeto
Estimated: at VDD=5 V, fully active CPU08 core, peripherals clocked, 8 MHz bus, the MC68HC908LJ24CFU typically draws 8-15 mA. At STOP with RTC running from 32.768 kHz, quiescent current drops to a few microamps. Designers building battery-backed meters must budget bulk capacitance so that STOP retention survives the longest expected line-voltage dropout and add a low-ESR bypass (10 uF + 0.1 uF) within 5 mm of VDD/VSS. For keypad and battery applications, route AVDD/AVSS separately and decouple VREFH/VREFL with a 100 nF ceramic to keep ADC noise below 1 LSB.
QFP-64 fine-pitch layout requires 0.4 mm land widths and a 4-layer stack-up with continuous ground planes to control LCD switching noise coupling into the ADC. Keep the 32.768 kHz RTC crystal within 5 mm of pins 60/61 with guard traces; route oscillator traces over the unbroken GND plane and never under switching traces. Place the bulk 10 uF bypass within 3 mm of the VDD pins and use a 4-via stitched copper pour under the QFP thermal pad for thermal and ground-rebound performance.
Do not leave the TEST pin (pin 63) floating; tie it to VDD in production or the device may enter test mode on reset. The CONFIG register sets LVR trip and timer-clock options and is locked after next reset - any CONFIG change requires careful re-lock. The RST pin needs an open-drain pull-up to VDD; the IRQ pin is edge/level selectable and should be debounced in firmware. Many LJ24 second-source issues stem from ignoring the LCD bias-capacitor sizing (typically 1 uF ceramic at Vlcd with a 100 k bias resistor ladder).
SPI and SCI traces above 1 MHz need series source-impedance control (typically 33 ohm) and ground-plane stitching vias every 5 mm. The 32.768 kHz RTC oscillator is sensitive to capacitor-load mismatch - choose a crystal with a 12.5 pF load specification and place the load caps within 2 mm of XOSC1/XOSC2. Avoid long parallel runs between high-current 12 V traces and segment-LCD outputs to prevent crosstalk into the bias voltages.
Informações de conformidade
RoHS / REACH / lead-free status not explicitly confirmed in the verified web data; verify with NXP or Rochester Electronics documentation. Not AEC-Q100 qualified - for AEC-Q100 designs cross-migrate to NXP S08 or S12K family.
