초록 ▼

An SRAM bit cell with cross-coupled inverters has separate write and read buses. Writing is performed through an NMOS pass transistor. Reading is performed through a PMOS transistor. Because the NMOS transistor does not pass a logic 1 as easily as logic 0, assistance is needed to speed up writing of

An SRAM bit cell with cross-coupled inverters has separate write and read buses. Writing is performed through an NMOS pass transistor. Reading is performed through a PMOS transistor. Because the NMOS transistor does not pass a logic 1 as easily as logic 0, assistance is needed to speed up writing of a logic 1 value relative to the time required to write a logic 0 value. An NMOS pre-charge transistor is coupled between the read bus and ground potential; and, a read is performed simultaneously with a write. This conditions the cell by weakening one of the inverters, such that they cross-couple more quickly when a logic 1 value is written into the cell. Alternatively, a single-ended read/write bus can be coupled to the NMOS pass transistor with write-assistance provided by grounding the PMOS pass transistor.

대표청구항 ▼

What is claimed is: 1. A memory bit cell comprising cross-coupled first and second inverters, each one of the inverters further comprising a pull-up transistor and a pull-down transistor having series-connected terminals defining a storage node, a first pass transistor coupled between a write bus a

What is claimed is: 1. A memory bit cell comprising cross-coupled first and second inverters, each one of the inverters further comprising a pull-up transistor and a pull-down transistor having series-connected terminals defining a storage node, a first pass transistor coupled between a write bus and a first one of the storage nodes, a second pass transistor coupled between a read bus and a second one of the storage nodes, the first pass transistor further coupled to a write enable line for controllably switching the first pass transistor on or off, the second pass transistor further coupled to a read enable line for controllably switching the second pass transistor on or off, and a pre-charge transistor coupled between the read bus and a logic low voltage reference signal source, wherein one of the first and second pass transistors is an NMOS transistor and the other one of the first and second pass transistors is a PMOS transistor.