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Noise Cancellation with Dummy Word Line

IP.com Disclosure Number: IPCOM000076717D
Original Publication Date: 1972-Apr-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Ho, IT: AUTHOR [+2]

Abstract

For high density monolithic memory, (either field-effect transistor (FET) or bipolar) using dynamic mode operation, noise coupling from a word line to a sense line can cause a problem in sensing. Information is written into a cell by storing or not storing a small amount of electric charges. Reading is performed by retrieving and sensing this amount of charges. The output voltage signal during read is generally quite small, due to the fact that the capacitance of the bit-sense line is substantially larger than the capacitance of a storage cell. The word line to sense-line noise in such a case tends to minimize the ratio of output voltages in reading a "1" and in reading a "0".

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Noise Cancellation with Dummy Word Line

For high density monolithic memory, (either field-effect transistor (FET) or bipolar) using dynamic mode operation, noise coupling from a word line to a sense line can cause a problem in sensing. Information is written into a cell by storing or not storing a small amount of electric charges. Reading is performed by retrieving and sensing this amount of charges. The output voltage signal during read is generally quite small, due to the fact that the capacitance of the bit-sense line is substantially larger than the capacitance of a storage cell. The word line to sense-line noise in such a case tends to minimize the ratio of output voltages in reading a "1" and in reading a "0".

Although the word line to sense-line noise coupling can be somewhat reduced by reducing the capacitance coupling between these two lines, this disclosure utilizes a dummy-word line which can theoretically reduce the word line to sense-line noise coupling to zero. The proposed technique should apply to all dynamic mode monolithic memories, especially for those memories which do not have an amplification mechanism to retrieve the stored charges in a cell to its sense line.

The word line WD in the drawing is designated as a dummy-word line. When a word such as that of W2 is read, a pulse is applied to W2. At the same time a pulse of opposite polarity is applied to WD. This WD pulse has the same rise time, the same amplitude and the same duration as the W...