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Method for Sensing Extra Cells on Ends of Dynamic Random-Access Memory Interdigitated Arrays

IP.com Disclosure Number: IPCOM000062490D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Davis, A: AUTHOR [+4]

Abstract

Two methods are described to access previously unused dynamic random- access memory (DRAM) cells at the ends of bit line array segments wherein bit lines are interdigitated for maximum space utilization. The presence of these cells, inclusive of bit line wiring, is the result of the repetitive layout process for memory arrays. Both methods employ "folded" (half wide, double high) sense amplifier design to connect to previously unconnected bit line segments at ends of interdigitated arrays of bit lines. Fig. 1 shows a first method comprised of attaching the folded sense amplifiers 2 to previously unconnected bit line segments 4. Sense amplifiers 6 internal to the array are of normal design dimensions. Only two of the word lines are shown.

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Method for Sensing Extra Cells on Ends of Dynamic Random-Access Memory Interdigitated Arrays

Two methods are described to access previously unused dynamic random- access memory (DRAM) cells at the ends of bit line array segments wherein bit lines are interdigitated for maximum space utilization. The presence of these cells, inclusive of bit line wiring, is the result of the repetitive layout process for memory arrays. Both methods employ "folded" (half wide, double high) sense amplifier design to connect to previously unconnected bit line segments at ends of interdigitated arrays of bit lines. Fig. 1 shows a first method comprised of attaching the folded sense amplifiers 2 to previously unconnected bit line segments 4. Sense amplifiers 6 internal to the array are of normal design dimensions. Only two of the word lines are shown. This method connects one of two cells driven by one word line to each side of a sense amplifier, thus having a signal and its complement stored for reference. Storage capacity added is therefor 1/2 the number of previously unused cells with this first method. A second method also uses the attachment of the folded sense amplifier 2 design to previously unused bit line segments 4 and is comprised of making bit line contact to cells controlled by alternate word lines as indicated by dot connections in Fig. 2. As indicated, all cells are connected to bit lines served by the normal sense amplifiers 6 internal to the array. As a result, only th...