Performance Comparison of Positive Feedback Match-Line (ML) Sensing Schemes for Low Power TCAM

Abstract: This paper presents a comparative performance analysis among different positive feedback based match line (ML) sensing scheme such as Mismatch dependent, Active feedback and Resistive feedback scheme. The comparison has been done based on parameters like search time, voltage margin, peak dynamic power and worst case energy consumption. Although most popular ML sensing scheme Current Race (CR) consumes more power than positive feedback based ML sensing scheme but performance comparison has also been shown between CR with each of three positive feedback based match line (ML) sensing scheme for equal search time. Finally, for search time Resistive feedback, for voltage margin and peak dynamic power consumption Mismatch dependent and for worse case energy consumption Active feedback scheme were found to be showing the best performance. For performance comparison the all the circuits is simulated using 130nm 1.2V CMOS logic.

Keywords: Ternary Content Addressable Memory (TCAM), positive feedback, Match Line Sensing Amplifier (MLSA), match line sensing scheme, current variation.