Synchronous circuit with improved clock to data output access time

Abstract

A synchronous circuit, such as an SRAM, a DRAM or a programmable logic device, has internal circuitry, a master input latch clocked by a master clock generator, and a slave output latch clocked by a slave clock generator. The master input latch is rendered transparent prior to the start of system setup time so that information input signals can pass through the master input latch and undergo processing in the circuitry prior to the start of a system cycle. After correct and stable information output signals are generated by the internal circuitry, these signals are latched into the slave output latch as correct and stable output information. The master latch may be clocked from the latched to the transparent state before the slave latch is clocked from the transparent to the latched state, provided that the time period between these two transitions is less than the minimum processing time of the internal circuitry. By advancing the start of the internal signal processing by a time period equal to the system setup time, the system clock to data output access time is substantially shortened.