A high performance BiCMOS 32-bit microprocessor

The authors have developed the world´s first BiCMOS 32-b single-chip microprocessor. It integrates 529 K transistors into a 12.98-mm² chip and typically realizes a 70-MHz frequency. The frequency is 1.5-2 times higher than that of current CMOS microprocessors. The microprocessor is designed to reduce the number of interchip communication signals in the critical path and to use basic cells optimally so as to allow fabrication into a single chip. The microprogram is divided into two parts, and frequently used microinstructions are stored in the ROM on the chip to reduce interchip communication. The translation lookaside buffer is also integrated in the microprocessor to reduce the interchip communication signals for memory access. Because of chip size and logic complexity constraints, less than 20% of the basic cells can be BiCMOS cells