Content-addressable memory (cam) cell with p and n pass gates to same write bit line

Abstract

A Content-Addressable Memory (CAM) cell has a latch of cross-coupled inverters and transmission gates to bit lines. Each transmission gate has n-channel and p-channel transistors in parallel that both turn on during writing. A node in the latch is applied to a gate of a data transistor in series with a select transistor to discharge a match line when select and latch data mismatch. Second data and select transistors receive inverse data from the latch for a CAM but receive data from a second cell latch for a Ternary Content-Addressable Memory (TCAM) cell with two latches per pair of select lines. When mismatches occur, even cells discharge the match line using n-channel data and select transistors while odd cells charge a complement match line using p-channel data and select transistors. The total number of p-channel and n-channel transistors in the cell can be equal when using complementary match lines.