Fast & Accurate Methodology for Aging Incorporation in Circuits using Adaptive Waveform Splitting (AWS)

Abstract

Fig. 1 Three workload profiles (cases -A, B, C) applied to a transistor under NBTI stress and the corresponding normalized degradation. During active mode, the frequency (=1GHz) and DF (=0.5) are fixed in all cases.

Overhead Reduction with Optimal Margining Using A Reliability Aware Design Paradigm

“…Aging related degradation mechanisms like NBTI are strongly a function of workload/activity pattern at the gate input of the transistor due to the observed recovery effects [4], [13]. In [10], an Adaptive Workload Splitting (AWS) algorithm and a long-term extrapolation methodology were proposed for fast calculation of NBTI degradation due to an arbitrary nonuniform activity pattern with excellent accuracy. It was also demonstrated in [10] at block level that, timing path violations could be minimized using these techniques.…”

“…In [10], an Adaptive Workload Splitting (AWS) algorithm and a long-term extrapolation methodology were proposed for fast calculation of NBTI degradation due to an arbitrary nonuniform activity pattern with excellent accuracy. It was also demonstrated in [10] at block level that, timing path violations could be minimized using these techniques. We utilize these schemes in this paper, in order to evaluate the PPA gains on a full chip, implemented using industry-standard EDA tool flow.…”

“…3: The proposed workload dependent aging aware design optimization flow. Workload analysis is performed on the routed design using AWS algorithm [10] and instance specific timing shifts (derate factors) are provided as constraints during design optimization.…”

“…Workload traces obtained from GLS on post-route design database are fed to the AWS algorithm [10] for estimation of degradation for each transistor in the design. Based on the workload averaging effect, the AWS algorithm essentially Fig.…”

“…Even though this "effective" stress consideration is sufficient under uniform activity scenarios, as in Fig. 2, it turns out that non-uniform activity, typically encountered in realistic circuits under application of true workloads, may potentially cause major discrepancy [9], [10].…”