Sense amplifier architecture for content addressable memory device
AssigneeNetLogic Microsystems, Inc.
InventorsAnita X. Meng, Eric H. Voelkel
Life of this patent
Estimating the term…
Abstract
A content addressable memory (CAM) device (200) can equalize a potential between a match line (202) and corresponding pseudo-supply (PVSS) line (204) in a pre-sense operation. In a sense operation, a sensing device (P4) can determine a match condition exists when the match line (202) potential varies from the PVSS line (204) potential. Complementary compare data lines (CD and BCD) can be equalized with one another in a pre-sense operation, while one compare data line (CD or BCD) can be equalized with bit lines (BB1 and/or BB2) in the sensing operation.
Claims22
A content addressable memory (CAM) device, comprising:
- a plurality of match lines, each coupled to a row of CAM cells;
- an electrically isolatable line corresponding to each match line and coupled to the match line by at least one equalization device;
- a charge circuit coupled between each electrically isolatable line and a first power supply node, each charge circuit having a controllable impedance path;
- and
- a sense device corresponding to each match line, each sense device generating a match indication when the potential of the match line varies from the potential of the corresponding electrically isolatable line.
A content addressable memory (CAM) device, comprising:
- a plurality of compare data line pairs that provide a compare data value to a plurality of CAM cell rows in a sensing period;
- and
- a compare data line driver circuit corresponding to each compare data line pair, each compare data line driver circuit including at least one driver equalization device that electrically connects one compare data lines of the pair to at least one electrically isolatable node in the sensing period and at least one pre-sensing equalization device that electrically connects the compare data lines of the pair to one another in a pre-sensing period, the pre-sensing period being different than the sensing period.
A method for sensing compare results in a content addressable memory (CAM) device, comprising the steps of:
- in a pre-sense period, equalizing match lines with corresponding electrically isolatable pseudo supply lines and setting sense nodes corresponding to each match line to mismatch levels;
- and
- in a sense period, generating a match indication at a match node when the corresponding match line differs in potential from the corresponding pseudo supply line.
Dependencies are inferred from the claim text.