A family of cells to reduce the soft-error-rate in ternary-CAM

Modern integrated circuits require careful attention to the soft-error rate (SER) resulting from bit upsets, which are normally caused by alpha particle or neutron hits. These events, also referred to as single-event upsets (SEUs), will become more problematic in future technologies. This paper presents a ternary content-addressable memory (CAM) design with high immunity to SEU. Conventionally, error-correcting codes (ECC) have been used in SRAMs to address this issue, but these techniques are not immediately applicable to CAMs because they depend on processing the full contents of the memory word outside the array, which is not possible in a normal CAM access. We propose a family of TCAM cells that reduce the SER at the cost of some area increase. An SER reduction of up to 40% can be obtained with a 18% increase of area; another design reduces the SER by 16% with only a 5% increase in area.