NXP Semiconductors MC705JJ7CDWE

Overview

MC705JJ7CDWE from Freescale Semiconductor is a 8-bit HCMOS microcontroller featuring 4 KB on-chip EPROM, 128 bytes RAM, and integrated analog subsystem including dual voltage comparators, 8-channel 8-bit ADC, and internal temperature sensor. It operates at up to 4 MHz with 5 V supply and supports multiple low-power modes (Stop, Wait, Halt, Data-Retention). Used in battery-powered industrial sensors and motor control feedback loops.

For engineers reviewing the MC705JJ7CDWE datasheet, MC705JJ7CDWE pinout, MC705JJ7CDWE application, or MC705JJ7CDWE equivalent, this page delivers verified technical context, validated pin functions, real-world use cases, and two confirmed alternative parts for design continuity-no speculation, no generic claims.

Technical Context

The MC705JJ7CDWE implements the M68HC05 CPU core with 32-byte stack, 8-bit accumulator, and 16-bit index register. Its memory map includes 4 KB EPROM (user-programmable), 128 B RAM, and dedicated I/O registers mapped to $00–$3F address space.

It integrates three timing peripherals: a 16-bit programmable timer with input capture/output compare, an 8-bit core timer with COP watchdog, and SIOP synchronous serial interface (master-only, 3-wire). Analog features include dual independent voltage comparators with interrupt capability and ratiometric/absolute A/D conversion support.

Key Specifications

Pinout & Package

MC705JJ7CDWE is housed in a 28-pin SOIC (Small Outline Integrated Circuit) package with 300 mil body width, JEDEC MS-012AC compliant, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68HC705JP7CDWE, MC705JJ7CDWE saves board space and BOM cost where Port C is unused; versus MC908JB8CDWE, it avoids FLASH wear-out concerns and simplifies programming infrastructure in fixed-function embedded systems.

Availability

MC705JJ7CDWE is available at Aetrix Electronics and suitable for industrial sensor nodes, motor feedback controllers, smart appliance control panels, and legacy system upgrade modules requiring stable component supply over extended product lifecycles.

Supply support for MC705JJ7CDWE 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 microcontrollers for cost-sensitive, low-power embedded applications in automotive, industrial, and consumer markets.

The MC68HC705 family was designed for resource-constrained control tasks requiring integrated analog I/O, deterministic real-time response, and long-term reliability without external memory or complex toolchains.

FAQ

What is the maximum operating frequency of the MC705JJ7CDWE?

The MC705JJ7CDWE operates at a maximum clock frequency of 4 MHz when powered at VDD = 5.0 V. This applies to all supported oscillator sources - crystal, ceramic resonator, RC network, or external clock - and is validated across commercial temperature range (0°C to +70°C). The MC705JJ7CDWE does not support frequencies above 4 MHz under any condition.

Does the MC705JJ7CDWE support in-system programming?

No, the MC705JJ7CDWE uses one-time-programmable EPROM and requires 12 V on the IRQ/VPP pin for programming via parallel EPROM programmer. It lacks on-chip FLASH or bootloader support, so firmware updates necessitate physical chip replacement. This design reflects its target use in fixed-function, high-reliability applications where field updates are unnecessary.

How many analog input channels does the MC705JJ7CDWE provide?

The MC705JJ7CDWE provides eight single-ended analog input channels (AN0–AN7), accessible through Port B pins PB0–PB7 with multiplexing controlled by the Analog Multiplex Register (AMUX). Channels AN4–AN7 also serve as comparator inputs (CMP1/CMP2), and all eight support both absolute and ratiometric A/D conversion modes.

Is the MC705JJ7CDWE pin-compatible with other members of the MC68HC705 family?

The MC705JJ7CDWE shares identical pinout and electrical characteristics with MC68HC705JJ7 variants (e.g., MC68HC705JJ7CDW, MC68HC705JJ7CP), but differs from MC68HC705JP7CDWE (adds Port C pins PC0–PC5) and MC68HC705SJ7 (20-pin SOIC). Pin compatibility is limited to the JJ7 suffix group; cross-referencing requires verification of package type (SOIC-28) and speed grade.

What low-power modes are implemented in the MC705JJ7CDWE?

The MC705JJ7CDWE implements four low-power modes: Stop (CPU and clocks halted, 0.5 µA typical), Wait (CPU stopped, clocks active, 10 µA), Halt (CPU and most peripherals halted, 2 µA), and Data-Retention (RAM retained, 1 µA). All modes wake on RESET, IRQ, or internal timer events, and retain register contents except core timer counter in Stop mode.