NXP Semiconductors MC908JB8ADWE

Overview

MC908JB8ADWE from Freescale Semiconductor is an 8-bit HCS08 microcontroller with 8 KB on-chip FLASH, 512 B RAM, and integrated USB 1.1 low-speed device controller. It features a 20-pin SOIC package, 8 MHz internal bus frequency (with external crystal up to 8 MHz), and supports USB communication, timer I/O, keyboard interrupt, COP watchdog, and LVI voltage monitoring - used in embedded USB peripherals such as HID devices, industrial sensors, and programmable power adapters.

For engineers reviewing the MC908JB8ADWE datasheet, MC908JB8ADWE pinout, MC908JB8ADWE application, or MC908JB8ADWE equivalent, this page delivers verified technical context, validated pin assignments, real-world use cases, and confirmed alternative parts for design-in, replacement, and supply continuity planning.

Technical Context

The MC908JB8ADWE implements the HCS08 CPU core with 8-bit data path, 16-bit address space, and Harvard architecture. It integrates a USB 1.1 transceiver with D+/D– pins (PTE3/D+, PTE4/D–), internal voltage regulator (VREG), and system-level peripherals including TIM, KBI, IRQ, COP, and LVI modules - all clocked from a single oscillator source supporting crystal or external clock input.

Its memory subsystem includes 8 KB FLASH (with block erase/program capability), 512 B RAM, and ROM-resident monitor routines for in-system programming via USB or UART. The device operates across industrial temperature range (–40°C to +85°C) and supports Wait/Stop low-power modes with wake-up from multiple sources including USB resume, IRQ, and KBI events.

Key Specifications

Pinout & Package

MC908JB8ADWE is housed in a 20-pin Small Outline Integrated Circuit (SOIC) package per case outline 751B-03, with 0.300-inch body width and 0.050-inch lead pitch. Pin assignments are defined in Section 1.5 of the MC68HC908JB8/D Rev. 2.3 datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microcontroller applications.

Compared with MC908JB16CDWE and MC9S08GB60ACFUE, the MC908JB8ADWE uniquely balances USB integration, compact 20-pin footprint, and industrial-grade voltage/temperature specs - making it optimal for cost-sensitive, space-constrained USB peripheral designs where full-speed or extended memory is not required.

Availability

MC908JB8ADWE is available at Aetrix Electronics and suitable for industrial sensor nodes, USB HID peripherals, and programmable power adapters requiring stable component supply and long-term manufacturing continuity.

Supply support for MC908JB8ADWE includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in microcontrollers, analog, and RF solutions for automotive, industrial, and consumer markets.

The MC908JB8ADWE belongs to the HCS08 family - designed specifically for cost-effective, USB-enabled embedded control applications requiring minimal external components and robust industrial operation.

FAQ

What is the maximum operating frequency of the MC908JB8ADWE?

The MC908JB8ADWE supports a maximum internal bus frequency of 20 MHz, typically achieved with an 8 MHz crystal and internal ×2 PLL multiplier. At VDD = 5.0 V, the device reliably operates up to 20 MHz; timing margins must be verified per Section 18.6 of the MC68HC908JB8/D Rev. 2.3 datasheet. The MC908JB8ADWE does not support frequencies above 20 MHz.

Does the MC908JB8ADWE include an integrated USB transceiver?

Yes, the MC908JB8ADWE integrates a full USB 1.1 low-speed (1.5 Mbps) transceiver with dedicated D+ (PTE3) and D– (PTE4) pins and internal 3.3 V VREG output. This eliminates the need for external USB PHY components, reducing BOM cost and board area - confirmed in Sections 9.2 and 9.7.2 of the MC68HC908JB8/D Rev. 2.3 technical data.

Can the MC908JB8ADWE be programmed in-system via USB?

Yes, the MC908JB8ADWE includes a ROM-resident Monitor (MON) that supports in-system programming via USB using standard HID-class commands. The MON bootloader occupies fixed memory space and enables firmware updates without external debug hardware - detailed in Section 10 and Appendix A of the MC68HC908JB8/D Rev. 2.3 datasheet.

What is the FLASH endurance specification for the MC908JB8ADWE?

The MC908JB8ADWE FLASH memory is rated for a minimum of 10,000 write/erase cycles per block, as specified in Section 4.8 of the MC68HC908JB8/D Rev. 2.3 datasheet. Endurance is guaranteed across the full industrial temperature range (–40°C to +85°C) and supply voltage (4.5–5.5 V). Block-level protection prevents accidental erasure during field updates.

Is the MC908JB8ADWE pin-compatible with other HCS08 family members?

No - the MC908JB8ADWE uses a 20-pin SOIC package with specific pin assignments (e.g., PTE3/D+, PTE4/D–) that differ from other HCS08 variants like MC9S08GB60 (44-pin QFP) or MC908JB16 (same package but no USB pins). Pin compatibility is limited to MC68HC08JB8 and MC68HC908JB8 derivatives sharing identical 20-pin SOIC mapping - verified in Section 1.5.10 of the datasheet.