Broadcom Corporation

Lsi Logic Corporation

Lsi Corporation

Joseph Eugene Glenn

Ruggero Castagnetti

Jonathan Alois Schmitt

Ramnath Venkatraman

Myron Buer

Douglas D Smith

A one-time programmable memory. The one-time programmable memory has an antifuse and a read circuit configured to read the antifuse. An isolation transistor couples the antifuse to the read circuit. The read circuit and the isolation transistor have different power domains.

One time programmable memory

A disclosed embodiment is a programmable memory cell comprising an elevated ground node having a voltage greater than a common ground node by an amount substantially equal to a voltage drop across a trigger point adjustment element. In one embodiment, the trigger point adjustment element can be a diode. The trigger voltage of the programmable memory cell is raised closer to a supply voltage when current passes through the trigger point adjustment element during a write operation. The programmable memory cell can comprise a pair of cross-coupled inverters, and first and second programmable antifuses that can be coupled to each inverter in the pair of cross-coupled inverters. Since the trigger voltage of the programmable memory cell is raised closer to the supply voltage, a programmed antifuse can easily reach below the trigger voltage and result in a successful write operation even when the supply voltage is a low voltage.

Programmable memory cell

Improved layouts of binary and ternary content addressable memory cells (BCAM and TCAM) are shown. A content addressable memory cell layout has a plurality of P+ diffusion areas and a plurality of N+ diffusion areas that do not enclose isolation regions and on which shallow trench isolation stress can exert minimal influence on the drive current of the memories. Further, all transistors in the content addressable memory cell layout are oriented in the same direction to avoid unintended variations in electrical performance. The CAM layouts are 'process friendly' to accommodate requirements of advanced process technologies such as the 90 nm process.

Compact ternary and binary CAM bitcell architecture with no enclosed diffusion areas

Two new ternary CAM bitcell design options are presented that provide compact layout solutions while maximizing matchline channels routing through the cells. In both layouts, the first inventive layout, an asymmetric layout of the 6T-SRAM bitcell is used to improve ease of layout, density, and performance of ternary CAM cells. In the second inventive layout, n-type diffusions for the SRAM bitcell and the comparison circuit are separated, creating a bitcell having a more even cell aspect ratio.

Growing community of inventors

Eden Prairie, MN, United States of America

Joseph Eugene Glenn