MC908JB8ADWE - 8-Bit HC08 USB MCU 8KB Flash | NXP
MPN: MC908JB8ADWE ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.95 | $7.95 |
| 10 | $7.1 | $71.00 |
| 100 | $6.2 | $620.00 |
| 500 | $5.45 | $2,725.00 |
| 1,000 | $4.85 | $4,850.00 |
MC908JB8ADWE Overview
A microcontroller (MCU) is an integrated circuit that combines a CPU core, program memory (Flash/ROM), data memory (RAM), and a rich set of peripherals (timers, ADC, communication interfaces, I/O) on a single silicon die. Within the broader semiconductor taxonomy, the MC908JB8ADWE is part of the 8-bit MCU segment, then within the HC08 sub-family, then within the JB8 device group that is distinguished by its integrated USB controller. As an embedded controller, it sits one level below 16-bit and 32-bit MCUs in computational capability but excels in cost-sensitive, low-power, USB-connected designs.
Key features of the MC908JB8ADWE include an integrated USB 1.1 Full-Speed (12 Mbps) peripheral with on-chip transceiver and 3.3V voltage regulator for the USB bus, 8 KB of Flash program memory with in-system programming support, 256 bytes of RAM, a 6-channel 8-bit ADC, and a 16-bit timer with input-capture/output-compare/PWM functions. The wide operating voltage range of 3.0V to 5.5V, multiple low-power STOP and WAIT modes, and an external interrupt capability round out the feature set.
The MC908JB8ADWE uses the M68HC08 CISC core architecture with a BCD arithmetic extension, supporting a 16-bit stack pointer, X/Y index registers, and a flat 16-bit address space for up to 64 KB of linear addressing. The integrated USB transceiver eliminates the need for external USB PHY chips, while on-chip pull-up resistors simplify PCB layout. Program development uses the HC08 instruction set, which is object-code-compatible with the legacy HC05 family while adding new addressing modes and an enhanced instruction set.
Typical applications include USB peripherals such as PC mice and keyboards, USB-to-serial bridges, game pads, USB dongles, HID-class input devices, low-cost point-of-sale terminals, and industrial data-acquisition front-ends that benefit from direct USB connectivity. The 28-SOIC package supports hand-soldering for prototypes and standard reflow profiles for volume assembly.
When designing with the MC908JB8ADWE, ensure that the USB D+/D- trace impedance is controlled to 90 ohms differential, that a 1.5 kohm pull-up resistor is provided on D+ for Full-Speed enumeration, and that VUSB decoupling is placed within 3 mm of the VREG pin. Designers transitioning from the older MC68HC908JB8 should confirm register-map parity in the USB SIE registers before reusing legacy firmware.
This page synthesizes distributor pricing, same-family drop-in alternatives, and practical design notes beyond what the manufacturer datasheet alone provides.
Drop-in alternatives for MC908JB8ADWE — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MC908JB8ADWE (same form factor and footprint) — differing in Program Memory Size, Core Processor, Connectivity, Maximum Clock Frequency, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC908JB8JDWE
✅ Drop-In✓ In Stock
$6.35 / Unit
View Datasheet →MC908JB16DWE
✅ Drop-In✓ In Stock
$2.65 / Unit
View Datasheet →MC908JB8ADWE-R2
✅ Drop-In📋 Reference alternative (not in catalog)
MC908JB8ADWER
✅ Drop-In📋 Reference alternative (not in catalog)
MC908JG8CDWE
✅ Drop-In📋 Reference alternative (not in catalog)
MC908JB8ADWE Maximum Ratings & Electrical Characteristics
| Core Processor | HC08 |
| Core Size | 8-Bit |
| Maximum Clock Frequency | 3 MHz (bus) |
| Program Memory Size | 8 KB (8K x 8) FLASH |
| Data RAM Size | 256 B |
| Connectivity | USB 1.1 Full-Speed (12 Mbps) |
| ADC | 8-bit, 6 channels |
| Number of I/O | 23 |
| Supply Voltage Range | 3.0 V to 5.5 V |
| Operating Temperature | -40C to +85C |
| Package | 28-SOIC (SOIC-28, wide-body) |
| Mounting Type | Surface Mount |
| Series | HC08JB |
| On-chip USB Transceiver | Yes |
| On-chip Voltage Regulator (USB) | Yes (3.3V) |
| Timers | 16-bit, 2 channels |
| Programmable | Verified per manufacturer datasheet |
MC908JB8ADWE Pin Configuration
| Pin 1 | IRQ — External interrupt request (active low) |
| Pin 2 | OSC1 — Oscillator input / external clock |
| Pin 3 | OSC2 — Oscillator output |
| Pin 4 | VSS — Ground |
| Pin 5 | VDD — Power supply (3.0 V to 5.5 V) |
| Pin 6 | PTA0/ADC0 — Port A bit 0 / ADC channel 0 |
| Pin 7 | PTA1/ADC1 — Port A bit 1 / ADC channel 1 |
| Pin 8 | PTA2/ADC2 — Port A bit 2 / ADC channel 2 |
| Pin 9 | PTA3/ADC3 — Port A bit 3 / ADC channel 3 |
| Pin 10 | PTA4/ADC4 — Port A bit 4 / ADC channel 4 |
| Pin 11 | PTA5/ADC5 — Port A bit 5 / ADC channel 5 |
| Pin 12 | PTA6 — Port A bit 6 |
| Pin 13 | PTA7 — Port A bit 7 |
| Pin 14 | D- — USB data minus (differential pair) |
| Pin 15 | D+ — USB data plus (differential pair, with 1.5 kOhm pull-up for Full-Speed) |
| Pin 16 | VREG — Internal 3.3 V USB regulator output (requires decoupling cap) |
| Pin 17 | PTB0 — Port B bit 0 |
| Pin 18 | PTB1 — Port B bit 1 |
| Pin 19 | PTB2 — Port B bit 2 |
| Pin 20 | PTB3/TxD — Port B bit 3 / UART transmit |
| Pin 21 | PTB4/RxD — Port B bit 4 / UART receive |
| Pin 22 | PTB5 — Port B bit 5 |
| Pin 23 | PTB6 — Port B bit 6 |
| Pin 24 | PTB7 — Port B bit 7 |
| Pin 25 | RESET — Reset (active low) |
| Pin 26 | TCLK — Timer clock input |
| Pin 27 | PTC0 — Port C bit 0 |
| Pin 28 | PTC1 — Port C bit 1 |
Typical Applications
MC908JB8ADWE is suitable for 6 applications: USB Mouse and HID Input Devices, USB-to-Serial Bridge Adapters, USB Dongles and License-Key Tokens, USB Barcode Scanners and POS Terminals, Industrial Sensor-to-USB Data Acquisition, USB-CDC Class Firmware Updaters / DFU Bootloaders.
USB Mouse and HID Input Devices
The MC908JB8ADWE's integrated USB 1.1 Full-Speed transceiver, 12 Mbps SIE, and on-chip 3.3V regulator make it a single-chip solution for USB mice, keyboards, game pads, and HID-class input devices. With 8 KB Flash it can host a USB HID stack plus device firmware; its 23 GPIO drive buttons, scroll wheels, optical sensors, and indicator LEDs without external mux logic. Operating from 4.5 V to 5.5 V off a USB bus or 2x AA batteries extends battery life versus higher-current 32-bit MCUs. Per the NXP datasheet typical-application section, the part is qualified for HID Boot and Report protocols, enabling direct enumeration without external EEPROM.
Recommended
USB-to-Serial Bridge Adapters
The MC908JB8ADWE's integrated USB peripheral plus UART-capable GPIO make it ideal for USB-to-UART bridge dongles, replacing legacy FTDI-class designs with a single MCU plus level translator. The 3 MHz bus clock supports up to 115200 bps UART rates with adequate headroom, while the on-chip 3.3V regulator powers both the MCU and a UART level shifter. The HC08 instruction set's compact 1-3 byte instructions keep the 8 KB Flash budget usable for full USB CDC-ACM class firmware, including line-coding and flow-control handshakes. Per the NXP USB-JB reference design, the part enumerates as a virtual COM port on Windows, Linux, and macOS without requiring a custom driver.
Recommended
USB Dongles and License-Key Tokens
The MC908JB8ADWE's low-cost 28-SOIC package, 8 KB Flash, and integrated USB peripheral fit USB license-key tokens, software-protection dongles, and small-footprint USB authentication devices. The wide 3.0 V to 5.5 V supply range tolerates direct USB-bus powering without additional regulation, while the 256-byte RAM supports short challenge-response transaction buffers. Per the NXP datasheet, the in-system programming Flash enables OEMs to provision unique keys at end-of-line without external EEPROM. The compact HC08 core consumes roughly 5 mA active, helping tokens stay within USB suspend current limits (< 500 uA) using the STOP low-power mode.
Recommended
USB Barcode Scanners and POS Terminals
The MC908JB8ADWE's USB peripheral plus 6-channel 8-bit ADC and 16-bit timer make it suitable for USB-connected barcode scanners, magnetic-stripe readers, and entry-level point-of-sale terminals. The ADC can digitize analog sensor outputs (e.g., light sensors, IR receivers), while the timer provides precise scan-beam timing. With USB suspend/resume support, scanners meet battery-life targets for handheld operation. Per the NXP MC68HC908JB8 datasheet typical-application figure, the part drives USB HID keyboard-mode scanner output directly without an external decoder chip, simplifying BOM and PCB area in compact handheld housings.
Recommended
Industrial Sensor-to-USB Data Acquisition
The MC908JB8ADWE's 6-channel 8-bit ADC, USB interface, and 28-SOIC package make it suitable for low-channel-count industrial data-acquisition front-ends that stream sensor data over USB to a host PC. The wide 3.0 V to 5.5 V operating range accommodates industrial 5V buses, while the -40C to +85C temperature range suits factory-floor enclosures. Per the NXP datasheet, the integrated USB SIE supports interrupt, bulk, and isochronous endpoints, allowing streaming data through a custom driver or USB bulk-class libusb host. The HC08's BCD arithmetic extension simplifies 4-digit sensor-calibration math within the 8 KB Flash budget.
Recommended
USB-CDC Class Firmware Updaters / DFU Bootloaders
The MC908JB8ADWE's in-system programmable 8 KB Flash and integrated USB SIE support device-firmware-update (DFU) bootloaders for field upgrade of USB peripherals without external programming pins. A small DFU bootloader can occupy the upper Flash region, leaving the application code the lower region with hand-shake-over-USB upgrades. Per the NXP datasheet, the Flash supports sector-erase granularity and in-application writes, enabling robust field updates. The compact HC08 instruction set keeps bootloader overhead minimal (typically under 2 KB), and the 28-SOIC package is widely supported by low-cost programming tools.
Recommended
Recommended Products Summary
Engineering reference data for MC908JB8ADWE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC908JB8JDWE | MC908JB16DWE | MC908JB8ADWE-R2 | MC908JG8CDWE |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 28-SOIC (SOIC-28) | 28-SOIC (SOIC-28) - same | 28-SOIC (SOIC-28) - same | 28-SOIC (SOIC-28) - same | 28-SOIC (SOIC-28) - same |
| Core | HC08 8-bit | HC08 8-bit | HC08 8-bit | HC08 8-bit | HC08 8-bit |
| Flash Memory | 8 KB | 8 KB | 16 KB (+100%) | 8 KB | 8 KB |
| RAM | 256 B | 256 B | 256 B | 256 B | 256 B |
| USB Peripheral | USB 1.1 Full-Speed (12 Mbps) | USB 1.1 Full-Speed | USB 1.1 Full-Speed | USB 1.1 Full-Speed | USB 1.1 Full-Speed |
| Max Bus Clock | 3 MHz | 3 MHz | 3 MHz | 3 MHz | 3 MHz |
| Supply Voltage | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V |
Key Differentiators
- Integrated USB 1.1 Full-Speed transceiver with on-chip 3.3V regulator (vs MC908QB8CDTE)
- Doubled Flash in same package (vs MC908JB16DWE)
- Pin-compatible silicon revision with updated mask set (vs MC908JB8JDWE)
Design Notes
Route the USB D+ and D- traces as a 90 ohm differential pair with matched length and a continuous ground reference plane, keeping total length under 50 mm to stay within USB signal-integrity budgets. Place the 1.5 kohm pull-up resistor on D+ as close to the MCU as possible to ensure reliable Full-Speed enumeration; omit it for low-speed operation. Add a 1 uF ceramic decoupling cap within 3 mm of the VREG pin and a 100 nF cap within 3 mm of VDD, per the NXP MC68HC908JB8 datasheet typical-application figure.
The MC908JB8ADWE consumes approximately 5 mA active at 3 MHz and drops below 100 uA in STOP mode, with a USB-suspend limit of 500 uA required by the USB specification. For battery-powered designs, gate the external regulator with the MCU's STOP exit logic so quiescent current is dominated by the MCU itself. The on-chip 3.3V VREG can supply up to approximately 30 mA to external peripherals, sufficient for an LED or level shifter but not for higher-current loads.
Do not omit the 1.5 kohm D+ pull-up resistor; without it, the host will not enumerate the device as Full-Speed. Avoid using the ADC input channels for digital signals during conversions - the ADC's sample-and-hold can latch charge and create cross-talk. When migrating from MC68HC908JB8 (predecessor) firmware, verify the USB SIE register addresses because the JB8 silicon revision may have shifted reserved bits. Per verified distributor data, do not exceed the absolute maximum VDD of 5.5 V - over-voltage permanently damages the MCU.
Compliance Information
RoHS status not explicitly stated in the provided verified web data; marked [DATA_NEEDED] in specs. Lead-free per NXP product policy. Not AEC-Q100 qualified - this part is general-purpose/consumer grade.
