The first System/370 microprocessor, the Micro/370 is a 32-bit processor that implements 102 System/370 instructions and sup-, ports the emulation of the rest of the instructions. The chip is 10 mmx 10 mm with 200,000 transistor sites, fabricated with a 2-micron polysilicon gate NMOS technology with two levels of aluminum. It is designed for 10 MHz clock at worst case and has been operated at 18 MHz with 3W power dissipation. Design tasks included maximizing the noise margin, minimizing noise, and being able to complete design changes in a short time. A mixed custom and standard-cell design approach was used in a hierarchical design and verification methodology. Copyright © 1987 by The Institute of Electrical and Electronics Engineers, Inc.