Architecture, design, and operating characteristics of a 12-ns CMOS functional cache chip

Abstract

The architecture, design, and implementation of a high-performance cache require a detailed consideration of the overall system functions closely coupled with the proper mapping and integration of these functions into the circuits and arrays. This approach has resulted in a new cache chip which incorporates a number of unique on-chip functions as well as unique design, providing a one-cycle cache in which translation can be overlapped with cache access. In order to achieve high average performance, a cache should give the appearance of being a two-ported array in order to provide high bandwidth both to the processor during normal execution and to the main memory during reload. A significant improvement can be obtained by judicious choice as well as proper integration of some critical functions placed directly on the cache chips. This paper describes these functions and integration onto a 72K-bit static RAM chip, implemented in 1-μm CMOS technology for high speed and overall system performance. In addition, the chip I/O is selectable for either ECL or TTL compatibility.