Static NAND cell for ternary content addressable memory (TCAM)

摘要

A static, ternary content addressable memory (TCAM) includes a key cell and a mask cell coupled to intermediate match lines. The key cell is coupled to a first pull-down transistor and a first pull-up transistor. The mask cell is coupled to a second pull-down transistor and a second pull-up transistor. The first pull-down transistor and second pull-down transistor are connected in parallel and the first pull-up transistor and second pull-up transistor are connected in series. A match line output is also coupled to the first pull-down transistor and second pull-down transistor and further coupled to the first pull-up transistor and second pull-up transistor.

主权项

1. A static, ternary content addressable memory (TCAM), comprising:
a first means for generating a comparison output based on a comparison of a search bit to a key bit, wherein a first pull-down transistor conducts and a first pull-up transistor does not conduct in response to the comparison output indicating a match between the search bit and the key bit, and wherein the first pull-down transistor does not conduct and the first pull-up transistor conducts in response to the comparison output indicating a mismatch between the search bit and the key bit; a second means for generating a mask output, wherein a second pull-down transistor conducts and a second pull-up transistor does not conduct in response to the mask output being asserted, and wherein the second pull-down transistor does not conduct and the second pull-up transistor conducts in response to the mask output being de-asserted, the first pull-down transistor and the second pull-down transistor being connected in parallel between a match line output and a first supply voltage terminal, and the first pull-up transistor and the second pull-up transistor being connected in series between a second supply voltage terminal and the match line output.