NXP Semiconductors MC68SEC000AA20

Overview

MC68SEC000AA20 from Motorola is a static 32-bit embedded microprocessor designed for ultra-low-power battery-operated systems. It delivers pin-for-pin compatibility with the MC68EC000, supports 3.3V/5.0V operation, achieves 20 MHz maximum clock speed, and consumes only 0.5 µA in static standby mode - enabling use in PDAs, portable test equipment, and handheld consumer electronics.

For engineers reviewing the MC68SEC000AA20 datasheet, MC68SEC000AA20 pinout, MC68SEC000AA20 application, or MC68SEC000AA20 equivalent, key selection criteria include static low-power operation, M68000 family object-code compatibility, 24-bit address/16-bit data bus configurability, and QFP/TQFP package options for space-constrained designs.

Technical Context

The MC68SEC000AA20 implements a fully static HCMOS version of the M68000 architecture, allowing clock suspension without state loss. Its internal 32-bit registers, 16-Mbyte linear addressing range, and 14 addressing modes support high-level language execution while maintaining hardware compatibility with legacy MC68EC000 systems.

It features asynchronous bus control via AS, R/W, UDS/LDS, and DTACK signals, supports seven interrupt levels with autovectoring (AVEC), and provides function code outputs (FC2–FC0) to identify supervisor/user mode and address space during bus cycles.

Key Specifications

Pinout & Package

MC68SEC000AA20 is supplied in a 64-lead plastic Quad Flat Pack (QFP) with 14.0 mm × 14.0 mm body size and 0.8 mm lead pitch, optimized for cost-sensitive industrial and consumer PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68EC000RC20 and MC68332ACPV16, the MC68SEC000AA20 uniquely balances M68000 software compatibility, ultra-low static power, and minimal external component requirements - making it optimal for battery-constrained, cost-sensitive, and space-limited embedded controllers where full peripheral integration is unnecessary.

Availability

MC68SEC000AA20 is available at Aetrix Electronics and suitable for portable medical instruments, industrial handheld testers, and consumer electronic games requiring stable component supply and long-term obsolescence management.

Supply support for MC68SEC000AA20 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

Motorola (now part of NXP Semiconductors) was a pioneering semiconductor innovator known for foundational microprocessor architectures and industrial-grade reliability.

The MC68SEC000AA20 belongs to Motorola's M68000 Family embedded processor line, engineered specifically for cost-sensitive, battery-powered 32-bit control applications demanding static operation and legacy software compatibility.

FAQ

What is the operating voltage range supported by the MC68SEC000AA20?

The MC68SEC000AA20 operates across two nominal supply rails: 3.3V ±0.3V and 5.0V ±0.5V. This dual-voltage capability allows direct integration into both modern low-power systems and legacy 5V industrial designs without level-shifting circuitry. The device maintains full functionality and timing specifications across both ranges, with standby current specified at 0.5 µA typical under 3.3V conditions.

Is the MC68SEC000AA20 pin-compatible with the MC68EC000?

Yes, the MC68SEC000AA20 is explicitly designed as a pin-for-pin replacement for the MC68EC000 in the 64-lead plastic QFP package. Signal names, pin locations, and electrical characteristics match identically, enabling direct PCB substitution. However, the MC68SEC000AA20 adds static operation and lower power consumption - enhancements that do not affect footprint or interconnect compatibility.

Does the MC68SEC000AA20 support 8-bit peripheral interfaces?

Yes, the MC68SEC000AA20 supports 8-bit data transfers via its MODE pin: when MODE is held low, the processor uses only D7–D0 for data, asserting LDS only and ignoring UDS. This allows seamless connection to legacy 8-bit peripherals such as UARTs, LCD controllers, and EEPROMs without external bus transceivers or address latching logic.

What is the maximum memory addressing capability of the MC68SEC000AA20?

The MC68SEC000AA20 implements a 24-bit address bus (A23–A0), enabling direct access to 16 Mbytes (2²⁴ bytes) of linear memory space. This covers separate regions for program code, data, and memory-mapped I/O - sufficient for standalone embedded applications using external flash, SRAM, and peripheral chips without memory management hardware.

How does the MC68SEC000AA20 achieve ultra-low standby current?

The MC68SEC000AA20 achieves 0.5 µA typical standby current through its fully static HCMOS design: all internal latches and registers retain state with zero clock activity, and internal bias circuits minimize leakage. Entering standby requires only assertion of the HALT signal - no software initialization or register writes are needed, ensuring reliable, instantaneous power-down and wake-up.