A 0.9-V MICROCONTROLLER FOR PORTABLE APPLICATIONS

A 0.9-1.6-V, 1-MHz, 8-b microcontroller based on the 68HC08 architectu re is presented. In addition to standard digital microcontroller funct ions, the chip features RAM, ROM, phase-locked loop (PLL) clock synthe sis, and liquid crystal displays (LCD) drive capabilities operating fr om the voltage supply range of a single AA or AAA battery. The design used a library of CMOS microcontroller building blocks, converted into a low-voltage technology using unilateral transistors. The design app roach was to optimize the conversion strategy for each functional bloc k and to provide new designs when the conversion was insufficient. The chip exceeded specifications with blocks showing full functionality d own to 0.7 V.