Mitel Semiconductor Limited

David Johnston

Richard Albon

Alan Martin

Martin Alan

A synchronous single port random access memory comprises a core,of memory cells,arranged as rows and columns. The rows are addressed by a row decoder,and the memory cell outputs are connected as columns to a column decoder and multiplexer,The decoder and multiplexer,selects groups of memory cells,from the addressed row and connects these to sense amplifiers,Changes in address are propagated immediately to the core,so that the selected memory cells,are connected as quickly as possible and without any fixed delays to the sense amplifiers,Similarly, a read clock &ldquo;rclk&rdquo; enables the sense amplifiers,immediately upon becoming active.

Synchronous memory

A semiconductor memory, for example of the ROM type, has columns of memory cells with a bitline for each column connected to the cells of the column. The bitlines are connected via multiplexers to the input of a sense amplifier. Before column selection, the bitlines are held uncharged. When a column is selected, its bitline is connected to a charging voltage by a pull up transistor.

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Tavistock, United Kingdom

David Johnston