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Distributed Filtering of Memory Array Lines

IP.com Disclosure Number: IPCOM000042964D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Kadlec, J: AUTHOR

Abstract

Distributed filtering reduces oscillations in currents transferred into array lines of a superconducting memory, without affecting the speed of transfer or the density of the array, and thus improves operating margins. The selected memory array lines require a fast and smooth (i.e., without oscillations) transfer of currents biasing or controlling the memory cell. The oscillations can be reduced by various damping schemes, including lumped LRC filters at several locations of the array lines (3 or 4 filters) and a line damping resistor across the line center. While this scheme is efficient in dealing with oscillations, it reduces the speed of current transfer and increases the size of the array.

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Distributed Filtering of Memory Array Lines

Distributed filtering reduces oscillations in currents transferred into array lines of a superconducting memory, without affecting the speed of transfer or the density of the array, and thus improves operating margins. The selected memory array lines require a fast and smooth (i.e., without oscillations) transfer of currents biasing or controlling the memory cell. The oscillations can be reduced by various damping schemes, including lumped LRC filters at several locations of the array lines (3 or 4 filters) and a line damping resistor across the line center. While this scheme is efficient in dealing with oscillations, it reduces the speed of current transfer and increases the size of the array. The distributed filtering scheme utilizes the "natural" inductances and capacitances of memory cells by bypassing them by an appropriate resistor which is incorporated into the cell layout. In this way, each cell (or part) acts as a filter in each of the array lines. The approach is illustrated with the example of the Y-line in the figures as follows: Fig. 1 shows schematically the storage loop of the cell with its "natural" L's & C's and WG-damping resistor. Fig. 2 shows schematically the storage loop after relocation of the resistor. Fig. 3 is the equivalent filter seen by the Y current. The benefits of this distributed filtering are: i) oscillations in transferred currents reduced at or below the level achieved by lumped filte...