The M68HC11 K-series microcontroller units (MCUs) are high-performance derivatives of the MC68HC11F1 and have several additional features. The MC68HC11K0, MC68HC11K1, MC68HC11K3, MC68HC11K4 and MC68HC711K4 comprise the series. These MCUs, with a nonmultiplexed expanded bus, are characterized by high speed and low power consumption. Their fully static design allows operation at frequencies from 4 MHz to dc. This document contains information concerning standard, custom-ROM, and extended-voltage devices. Standard devices include those with disabled ROM (MC68HC11K1), disabled EEPROM (MC68HC11K3), disabled ROM and EEPROM (MC68HC11K0), or EPROM replacing ROM (MC68HC711K4). Custom-ROM devices have a ROM array that is programmed at the factory to customer specifications. Extended-voltage devices are guaranteed to operate over a much greater voltage range (3.0 Vdc to 5.5 Vdc) at lower frequencies than the standard devices. Refer to the device ordering information tables for details concerning these differences.