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CMOS Sense Amplifier with increased Stability

IP.com Disclosure Number: IPCOM000111555D
Original Publication Date: 1994-Mar-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Helwig, K: AUTHOR [+3]

Abstract

This article describes how a CMOS sense amplifier, after a six-device cell, can be provided with more stability if, for system reasons, only one bit line is provided, and the latch is unsymmetrical in view of the manufacturing process.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 91% of the total text.

CMOS Sense Amplifier with increased Stability

      This article describes how a CMOS sense amplifier, after a
six-device cell, can be provided with more stability if, for system
reasons, only one bit line is provided, and the latch is
unsymmetrical in view of the manufacturing process.

      In such a case the sense amplifier has to be adjusted very
accurately, especially if a latch function parallel to the sense
amplifier is provided.  This is very difficult.  As shown in Fig. 1,
the bit line signal DBA is initiated by the word line signal WLA when
going 'high'.  Before it is allowed for DBA to be active at the sense
amplifier (by switching up SSA), PSA must have reached the high level
and switched off T6S.  Before that, the PSA has caused D01A and D02A
to have nearly the same potential.  As soon as T6S is switched off
but the sense amplifier does not amplify in the maximum extent, the
sense signal can be disturbed or delayed, respectively, by a small
potential difference between the nodes D01A and D02A, initiated by
the latch consisting of transistors T1S, T2S, T7S und T8S.

      As shown in Fig. 2, a simple but effective enhancement can be
obtained by implementing a transistor T10S connecting the common node
of T7S and T8S to GND, and having its gate connected to PSA.  The
disturbing latch current is switched off at the beginning of the
sense signal.  Then, after the node AY has been drawn to GND by the
rising PSA pulse, the latch current can start...