NXP Semiconductors MC908KX8CDWE

Overview

MC908KX8CDWE from Freescale Semiconductor is an 8-bit M68HC08 core microcontroller with 8 KB on-chip FLASH, 512 B RAM, integrated 8-channel 8-bit ADC, and programmable internal clock generator (ICG) supporting DCO-based frequency synthesis. It operates from 4.5 V to 5.5 V across –40°C to +125°C and targets automotive body electronics, industrial sensor interfaces, and low-cost motor control.

For engineers reviewing the MC908KX8CDWE datasheet, MC908KX8CDWE pinout, MC908KX8CDWE application, or MC908KX8CDWE equivalent, this page delivers verified electrical specs, ICG trim register behavior, IRQ1 pullup resistor values (19–43 kΩ), ADC conversion timing, and real-world use cases in battery-powered embedded systems requiring robust LVI and COP watchdog protection.

Technical Context

The MC908KX8CDWE integrates a digitally controlled oscillator (DCO) with modulo-N divider and digital loop filter for self-calibrating clock generation, eliminating external crystals in cost-sensitive designs. Its ICG supports dynamic frequency switching between 1 MHz and 8 MHz nominal outputs, with trim register (TRIM7:TRIM0) enabling ±15% fine-tuning at 25°C.

It features a dedicated Keyboard Interrupt Module (KBI) for matrix keypad scanning with debouncing support, and a Low-Voltage Inhibit (LVI) circuit with selectable trip points (4.25 V/4.0 V) and hysteresis-critical for brown-out resilience in 12 V automotive subsystems. The IRQ1 pin includes an internal 19–43 kΩ pullup resistor, confirmed per Rev. 3 addendum.

Key Specifications

Pinout & Package

MC908KX8CDWE is housed in a 28-pin SOIC (Small Outline Integrated Circuit) package with 300 mil width, JEDEC MS-012AC compliant, and lead-free (Pb-free) finish per RoHS.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with MC908KX8CDWE, the MC908KX2CDWE offers identical architecture and peripherals at lower memory capacity, while the MC9RS08KA2CSC trades KBI and FLASH size for modern debug capability and lower active current - neither is pin-compatible, and both require PCB layout revision.

Availability

MC908KX8CDWE is available at Aetrix Electronics and suitable for automotive body control, industrial sensor nodes, and medical device interface applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC908KX8CDWE 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) pioneered 8-bit automotive microcontrollers with robust qualification, high-temp reliability, and integrated analog peripherals.

The MC908KX8CDWE belongs to the M68HC08 family designed specifically for cost-sensitive, thermally demanding embedded control - emphasizing on-chip clock flexibility, interrupt-rich I/O, and fail-safe features like COP and LVI.

FAQ

What is the maximum operating frequency of the MC908KX8CDWE?

The MC908KX8CDWE supports a maximum internal bus frequency of 8 MHz, achieved via its digitally controlled oscillator (DCO) and modulo-N divider. This frequency is achievable across the full –40°C to +125°C range when calibrated using the ICG Trim Register (TRIM7:TRIM0), and is confirmed in Section 7.3.2.1 of the Rev. 2.1 datasheet and Addendum Rev. 3. The MC908KX8CDWE does not require external clock sources to reach this speed.

Does the MC908KX8CDWE include an internal pullup resistor on the IRQ1 pin?

Yes, the MC908KX8CDWE includes an internal pullup resistor on the IRQ1 pin with a guaranteed range of 19 kΩ (min) to 43 kΩ (max) at VDD = 5.5 V and TA = –40°C to +125°C, as specified in the October 2014 Addendum to Rev. 2.1 (Section 17.5). This eliminates the need for an external pullup in most switch-detection applications.

Can the MC908KX8CDWE operate without an external crystal?

Yes, the MC908KX8CDWE can operate fully without an external crystal by using its internal digitally controlled oscillator (DCO) as the system clock source. The ICG module allows configuration of the DCO output frequency (1–8 MHz nominal) and trimming via the ICG Trim Register. External crystal is optional and used only when higher precision or stability is required.

What is the ADC resolution and channel count of the MC908KX8CDWE?

The MC908KX8CDWE integrates an 8-bit successive-approximation analog-to-digital converter (ADC) with 8 input channels (AD0–AD7 mapped to PTB0–PTB7). Conversion time is ≤25 µs per sample at maximum bus frequency, and it supports single-ended operation referenced to VREFH. These specifications are detailed in Chapter 3 of the Rev. 2.1 datasheet.

Is the MC908KX8CDWE qualified for automotive applications?

Yes, the MC908KX8CDWE is AEC-Q100 qualified for automotive use, with guaranteed operation from –40°C to +125°C and built-in features essential for vehicle environments - including Low-Voltage Inhibit (LVI) with selectable 4.25 V/4.0 V trip points, Computer Operating Properly (COP) watchdog, and robust ESD tolerance. Its SOIC package and FLASH endurance further support automotive production requirements.