This paper presents a new logic style, named Current-Mode Differential logic (CMDL), that achieves both high operating speed and low power consumption. Inspired by the low-voltage swing (LVS) logic, CMDL uses a shunt resistor at the differential output to obtain constant low swing signal without the need to reset low. Furthermore, conditional shunt transistors are used for the internal nodes to prevent high-voltage swing, thus entirely eliminate the power-hungry clocked reset network in LVS circuits. We show that the CMDL is suitable for high-end microprocessor integer core by providing three datapath modules implemented in CMDL. Our simulation results indicate that, operating at comparable speed with LVS logic, CMDL circuits can achieve up to 50% reduction of delay-power product compared to CMOS logic and LVS logic. In addition, CMDL reduces the power consumption of LVS by up to 40%.

This paper optimizes timing and power consumption of mixed-radix Ling adders with the physical area constraints using an integer linear programming formulation. Each cell in the prefix network is flexible to have different radix and size, and Ling carries are incorporated. Optimal solutions are obtained by solving the proposed formulation. The experiments show that the produced optimal structures have a large power saving compared with traditional designs. The ASIC implementation results are superior to those produced by Synopsys Module Compiler.

A low power passive equalizer using RL terminator is proposed and optimized in this work. The equalizer includes an inductor in series with the resistive terminator, which boosts high frequency components and therefore improves the interconnect bandwidth with little overhead on power consumption. An analytic estimation method for eye-opening and jitter based on tritonic step response is also introduced in this work, which enables the optimization procedure. Our experimental results show that our estimation method is accurate and a board level transmission line of 50cm wire length can achieve 15Gb/s data rate. With 15GHz frequency input, the power consumption of the equalizer is less than 2.5mW, and the total power is 5mW.

Parallel prefix adder is the most flexible and widely-used binary adder for ASIC designs. Many high-level synthesis techniques have been developed to find optimal prefix structures for specific applications. However, the gap between these techniques and back-end designs is increasingly large. In this paper, we propose an integer linear programming method to build minimal-power prefix adders within given timing and area constraints. It counts both gate and wire capacitances in the timing and power models, considers static and dynamic power consumptions, and can handle gate sizing and buffer insertion to improve the performance further. The proposed method is also adaptive for non-uniform arrival time and required time on each bit position. Therefore our method produces the optimum prefix adder for realistic constraints.

We extend the surfliner on-chip distortionless transmission line scheme and provide more details for the implementation issues. Surfliner seeks to approach distortionless transmission by intentionally adding shunt resistors between the signal line and the ground. In theory if we distributively make the shunt conductance G=RC/L, there is no distortion at the receiver end and the signal propagates at the speed of light. We show the feasibility and advantages of this shunt resistor scheme by a real design case of single-ended microstrip line in 0.10mum technology. The simulation results indicate we can achieve near perfect signaling of 10 Gbps data over a 10 mm serial link, yet no pre-emphasis/equalization or other special techniques are needed. Guidelines for determining the optimal value and spacing of the shunt resistors are also provided.

We propose two orthogonal approaches to logarithmic cyclic shifter design. The first method, called fanout splitting, replaces multiplexers in a conventional design with demultiplexers which have two fanouts driving the shifting and non-shifting paths separately. The use of demultiplexers has a two-fold effect; it cuts the accumulated wire load on the critical path from O(Nlog2(N)) to O(N), and reduces the switching probabilities on the inter-stage long wires from 1/4 to 3/16. We then perform cell order optimization to further improve the delay, and formulate it as an integer linear programming problem. For the 64-bit case, the two approaches together reduce the total delay by 67.1% and dynamic power consumption by 17.6%, respectively.

This paper develops a novel high-speed inter-chip serial signaling scheme with leakage shunt resistors and termination resistors between the signal trace and the ground. For given abstract topology transmission line based on the data for IBM high-end AS/400 system[1] [2], we put termination resistors at the end of receiver and adjust the shunt and termination resistors value to get the optimal distortion-less transmission line. Analytical formulas are derived to predict the worst case jitter and eye-opening based on bitonic step Response Assumption[3]. Our schemes and the other two comparison cases are discussed.

A parallel prefix circuit has n inputs x 1 , x 2 , …, x n , and computes the n outputs y i = x i • x i −1 •…• x 1 , 1 ≤ i ≤ n , in parallel, where • is an arbitrary binary associative operator. Snir proved that the depth t and size s of any parallel prefix circuit satisfy the inequality t + s ≥2 n −2. Hence, a parallel prefix circuit is said to be of zero-deficiency if equality holds. In this article, we provide a different proof for Snir's theorem by capturing the structural information of zero-deficiency prefix circuits. Following our proof, we propose a new kind of zero-deficiency prefix circuit Z ( d ) by constructing a prefix circuit as wide as possible for a given depth d . It is proved that the Z ( d ) circuit has the minimal depth among all possible zero-deficiency prefix circuits.

Parallel prefix adder is a general technique for speeding up binary addition. In unit delay model, we denote the size and depth of an n-bit prefix adder C(n) as SC(n) and dC(n) respectively. Snir proved that sC(n) + dC(n) ≥ 2n - 2 holds for arbitrary prefix adders. Hence, a prefix adder is said to be of zero-deficiency if sC(n) + dC(n) = 2n - 2. In this paper, we first propose a new architecture of zero-deficiency prefix adder dubbed Z(d), which provably has the minimal depth among all kinds of zero-deficiency prefix adders. We then design a 64-bit prefix adder Z64, which is derived from Z(d)|d=8, and compare it against several classical prefix adders of the same bit width in terms of area and delay using logical effort method. The result shows that the proposed Z(d) adder is also promising in practical VLSI design.