Test Solution for Data Retention Faults in Low-Power SRAMs

Abstract

Low-power SRAMs embed mechanisms for reducing static power consumption. When the SRAM is not accessed during a long period, it switches into an intermediate low-power mode. In this mode, a voltage regulator is used to reduce the voltage supplied to the core-cells as low as possible without data loss. Thus, faulty-free behavior of the voltage regulator is crucial for ensuring data retention in core-cells when the SRAM is in low-power mode. This paper investigates the root cause of data retention faults due to voltage regulator malfunctions. This analysis is done under realistic conditions (i.e., industrial core-cells affected by process variations). Based on this analysis, we propose an efficient test flow for detecting data retention faults in low-power SRAMs.