17,027 research outputs found
Indicating Asynchronous Array Multipliers
Multiplication is an important arithmetic operation that is frequently
encountered in microprocessing and digital signal processing applications, and
multiplication is physically realized using a multiplier. This paper discusses
the physical implementation of many indicating asynchronous array multipliers,
which are inherently elastic and modular and are robust to timing, process and
parametric variations. We consider the physical realization of many indicating
asynchronous array multipliers using a 32/28nm CMOS technology. The
weak-indication array multipliers comprise strong-indication or weak-indication
full adders, and strong-indication 2-input AND functions to realize the partial
products. The multipliers were synthesized in a semi-custom ASIC design style
using standard library cells including a custom-designed 2-input C-element. 4x4
and 8x8 multiplication operations were considered for the physical
implementations. The 4-phase return-to-zero (RTZ) and the 4-phase return-to-one
(RTO) handshake protocols were utilized for data communication, and the
delay-insensitive dual-rail code was used for data encoding. Among several
weak-indication array multipliers, a weak-indication array multiplier utilizing
a biased weak-indication full adder and the strong-indication 2-input AND
function is found to have reduced cycle time and power-cycle time product with
respect to RTZ and RTO handshaking for 4x4 and 8x8 multiplications. Further,
the 4-phase RTO handshaking is found to be preferable to the 4-phase RTZ
handshaking for achieving enhanced optimizations of the design metrics.Comment: arXiv admin note: text overlap with arXiv:1903.0943
Latency Optimized Asynchronous Early Output Ripple Carry Adder based on Delay-Insensitive Dual-Rail Data Encoding
Asynchronous circuits employing delay-insensitive codes for data
representation i.e. encoding and following a 4-phase return-to-zero protocol
for handshaking are generally robust. Depending upon whether a single
delay-insensitive code or multiple delay-insensitive code(s) are used for data
encoding, the encoding scheme is called homogeneous or heterogeneous
delay-insensitive data encoding. This article proposes a new latency optimized
early output asynchronous ripple carry adder (RCA) that utilizes single-bit
asynchronous full adders (SAFAs) and dual-bit asynchronous full adders (DAFAs)
which incorporate redundant logic and are based on the delay-insensitive
dual-rail code i.e. homogeneous data encoding, and follow a 4-phase
return-to-zero handshaking. Amongst various RCA, carry lookahead adder (CLA),
and carry select adder (CSLA) designs, which are based on homogeneous or
heterogeneous delay-insensitive data encodings which correspond to the
weak-indication or the early output timing model, the proposed early output
asynchronous RCA that incorporates SAFAs and DAFAs with redundant logic is
found to result in reduced latency for a dual-operand addition operation. In
particular, for a 32-bit asynchronous RCA, utilizing 15 stages of DAFAs and 2
stages of SAFAs leads to reduced latency. The theoretical worst-case latencies
of the different asynchronous adders were calculated by taking into account the
typical gate delays of a 32/28nm CMOS digital cell library, and a comparison is
made with their practical worst-case latencies estimated. The theoretical and
practical worst-case latencies show a close correlation....Comment: arXiv admin note: text overlap with arXiv:1704.0761
Impact Ionization and Hot-Electron Injection Derived Consistently from Boltzmann Transport
We develop a quantitative model of the impact-ionizationand hot-electron–injection processes in MOS devices from first principles. We begin by modeling hot-electron transport in the drain-to-channel depletion region using the spatially varying Boltzmann transport equation, and we analytically find a self consistent distribution function in a two step process. From the electron distribution function, we calculate the probabilities of impact ionization and hot-electron injection as functions of channel current, drain voltage, and floating-gate voltage. We compare our analytical model results to measurements in long-channel devices. The model simultaneously fits both the hot-electron- injection and impact-ionization data. These analytical results yield an energydependent impact-ionization collision rate that is consistent with numerically calculated collision rates reported in the literature
Concepts for on-board satellite image registration. Volume 3: Impact of VLSI/VHSIC on satellite on-board signal processing
Anticipated major advances in integrated circuit technology in the near future are described as well as their impact on satellite onboard signal processing systems. Dramatic improvements in chip density, speed, power consumption, and system reliability are expected from very large scale integration. Improvements are expected from very large scale integration enable more intelligence to be placed on remote sensing platforms in space, meeting the goals of NASA's information adaptive system concept, a major component of the NASA End-to-End Data System program. A forecast of VLSI technological advances is presented, including a description of the Defense Department's very high speed integrated circuit program, a seven-year research and development effort
Asynchronous Early Output Dual-Bit Full Adders Based on Homogeneous and Heterogeneous Delay-Insensitive Data Encoding
This paper presents the designs of asynchronous early output dual-bit full
adders without and with redundant logic (implicit) corresponding to homogeneous
and heterogeneous delay-insensitive data encoding. For homogeneous
delay-insensitive data encoding only dual-rail i.e. 1-of-2 code is used, and
for heterogeneous delay-insensitive data encoding 1-of-2 and 1-of-4 codes are
used. The 4-phase return-to-zero protocol is used for handshaking. To
demonstrate the merits of the proposed dual-bit full adder designs, 32-bit
ripple carry adders (RCAs) are constructed comprising dual-bit full adders. The
proposed dual-bit full adders based 32-bit RCAs incorporating redundant logic
feature reduced latency and area compared to their non-redundant counterparts
with no accompanying power penalty. In comparison with the weakly indicating
32-bit RCA constructed using homogeneously encoded dual-bit full adders
containing redundant logic, the early output 32-bit RCA comprising the proposed
homogeneously encoded dual-bit full adders with redundant logic reports
corresponding reductions in latency and area by 22.2% and 15.1% with no
associated power penalty. On the other hand, the early output 32-bit RCA
constructed using the proposed heterogeneously encoded dual-bit full adder
which incorporates redundant logic reports respective decreases in latency and
area than the weakly indicating 32-bit RCA that consists of heterogeneously
encoded dual-bit full adders with redundant logic by 21.5% and 21.3% with nil
power overhead. The simulation results obtained are based on a 32/28nm CMOS
process technology
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