A match-line dynamic energy reduction technique for high-speed ternary CAM using dual feedback sense amplifier

• An energy efficient match-line sensing scheme for high-speed ternary CAM is presented.
• Positive feedback has been used twice in the match-line sense amplifier.
• Match detection is done with small match-line voltage making energy consumption low.
• The scheme offers high search speed and large voltage margin as well.
• The effects of PVT variations can be offset by adjusting a bias voltage.

Ternary content addressable memory (TCAM) has become popular in applications requiring high-speed table lookup. This paper presents a match-line (ML) sensing scheme to reduce dynamic energy consumption in MLs during the table lookup operation. Positive feedback has been used twice in the ML sense amplifier to achieve improved performance over existing schemes employing single feedback. Post-layout simulation of the scheme implemented using 180 nm 1.8 V CMOS logic shows that it can have match detection time as small as 907 ps. The scheme can also provide large voltage margin of 734 mV. Compared to popular current-race sensing scheme, the proposed scheme offers 83.8% energy reduction. It can achieve 64.5%, 74.7% and 77.8% energy savings compared to existing feedback schemes namely mismatch dependent, active feedback and resistive feedback, respectively. The energy saving is even larger for more advanced technology node.