CMOS/bipolar circuits for 60-MHz digital processing

High-performance bipolar/CMOS (Hi-BiCMOS) technology, in which a bipolar transistor of 4-GHz cutoff frequency is combined with standard CMOS devices on the same chip, has been applied to a processor. The design strategy was to provide high integration density using the CMOS circuit and accelerate the critical paths using the Hi-BiCMOS circuits. Hi-BiCMOS circuits with low-voltage swing have been developed and applied to a 32-bit arithmetic logic unit and a 128-kb ROM with bipolar drivers to drive a heavy load capacitance. A 17-ns 32-bit carry propagation delay time and a 17-ns ROM access cycle time have been achieved using 2-μm Hi-BiCMOS technology. A minicomputer CPU with a 60-MHz machine cycle can be implemented with these circuits.