In this paper a new family of scan flip-flops is introduced whose scan pin hold characteristic has improved while data pin timing is left intact. This characteristic helps to alleviate scan chain hold problem while meeting the maximum frequency in data path. This solution can reduce the number of buffers inserted in the scan chain to fix hold violations. The new flip-flop can save up to 29% area as compared to the usage of normal flip-flop combined with hold-fixing buffers.

Static timing analysis (STA) techniques allow a designer to check the timing of a circuit at different process corners, which typically include corner values of the supply voltages as well. Traditionally, however, this analysis only considers cases where the supplies are either all low or all high. As will be demonstrated, this may not yield the true maximum delay of a circuit because it neglects the possible mismatch between the supplies of successive gates on a path. A new methodology for timing analysis is proposed, where, in a first step, the critical paths of a circuit are identified under an assumption that all the supply nodes are independent of one another, thus allowing for mismatch between the supplies. Then, given these critical paths, the authors incorporate into the analysis the relationships between the supply node voltages by considering the power grid that they are tied to, and refine the worst case time delay values on a per-critical-path basis. This refinement is posed as a sequence of optimization problems where the operation of the circuit is abstracted in terms of current constraints. The authors present their technique and report on the implementation results using benchmark circuits tied to a number of test-case power grids

Current Static Timing Analysis (STA) techniques allow one to verify the timing of a circuit at different process corners which only consider cases where all the supplies are low or high. This analysis may not give the true maximum delay of a circuit because it neglects the possible mismatch between drivers and loads. We propose a new approach for timing analysis in which we first identify the critical path(s) of a circuit using a power-supply-aware timing model. Given these critical paths, we then take into account how the power nodes of the gates on the critical path are connected to the power grid, and re-analyze for the worst-case time delay. This re-analysis is posed as an optimization problem where the complete operation of the entire circuit is abstracted in terms of current constraints. We present our technique and report on the implementation results using benchmark circuits tied to a number of test-case power grids.