A comparative study on performance and reliability of 32-bit binary adders

作者：Bahadori Milad; Kamal Mehdi; Afzali Kusha Ali^*; Pedram Massoud

来源：Integration, the VLSI Journal, 2016, 53: 54-67.

DOI：10.1016/j.vlsi.2015.12.002

• Binary adders
• Aggressive supply voltage scaling
• Superthreshold
• Near-threshold
• Performance
• Reliability
• Process variation
• Negative bias temperature instability (NBTI)

In this paper, the performance and reliability of different binary adder families are studied for both the superthreshold and the near-threshold regions of operation. The adder structures are selected from both the carry propagate adders (CPAs) and parallel prefix adders (PPAs). The performance parameters which are used in the comparative study include delay, power, energy, and energy-delay-product (EDP) of the adders. Additionally, the impacts of the process variation and negative bias temperature instability (NBTI) on the delays of the adders under the aggressive supply voltage scaling are investigated. Also, the efficacies of the adders are compared using a merit function based on their performance and reliability parameters for a wide range of supply voltage levels, from the nominal voltage down to the near threshold voltage. The study is performed for the 32-bit adder structures designed based on the 14-nm FinFET and 45-nm bulk CMOS technologies. The results which are obtained using HSPICE simulations, reveal that the reliability parameters similar to the performance parameters are a function of the adder architectures and those are the key components to determine the efficiencies of the adders. Also, the results show that the impacts of the process variation and NBTI on the delays of the high performance PPA structures are more than those of the CPA structures for the whole range of the supply voltage. The PPAs, however, have the higher merit factors compared to the CPAs under a wide range of supply voltage levels. The results presented in this paper may provide some guidelines for the designers to select proper adder structures based on their design requirements and constraints.

• 出版日期2016-3