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2006 Conference Best Paper Awards
Best Regular Paper
The Best Regular Paper, “Self-Referenced Sense
Amplifier for Across-Chip-Variation Immune Sensing in High-Performance
Content-Addressable Memories” by Arsovski
and Wistort from IBM,
presents an excellent example of how innovative circuit techniques can effectively
and elegantly cope with ever increasing transistor variations. The self-referenced sense scheme
(SRSS), which is equally applicable to a number of single-ended sensing
memory applications (such as ROM, RA, 8T SRAM, and DRAM etc.), precharges each individual sense-line to a unique
voltage level slightly above the corresponding sense amplifier’s (SA)
threshold. The small and
constant delta between the precharge and
sense voltage for each SA across the chip effectively cancels out
transistor variations, reduces the timing uncertainty caused by
variation in the sense current (which in turn is caused by variations  in minimum-size memory cells), and
reduces power consumption thanks to the lowered sense-line voltage
swing. Consequently, the minimum
sense-delay required to bound the data-arrival for SRSS is greatly
reduced, yielding overall 60-70% improvement in sense time compared
with previous single-ended sensing schemes. The SRSS technique and its tolerance
to noise and subthreshold leakage is further enhanced by using Schmitt trigger
sensing, additional keeper devices, and layout techniques. Its superior performance, power
efficiency, and robustness is demonstrated in
the search operation implementation of a 64x240bit ternary
Content-Addressable Memory testchip
fabricated in 1V, 65nm CMOS.
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