Abstract: A register file apparatus and method incorporating read-after-write blocking using detection cells provides improved read access times in high performance register files. One or more detection cells identical to the register file cells and located in the register file array are used to control the read operation in the register file by configuring the detection cells to either alternate value at each write or change to a particular value after a write and then detecting when the write has completed by detecting the state change of an active detection cell. The state change detection can be used to delay the leading edge of a read strobe or may be used in the access control logic to delay generation of a next read strobe. The register file thus provides a scalable design that does not have to be tuned for each application and that tracks over voltage and clock skew variation.

Abstract: A dynamic-static logical control element for signaling an interval between the end of a control signal and a logical evaluation provides a compact circuit for blocking the indication of a non-evaluated state of a dynamic logic gate until a control signal has ended. The control signal is connected to a precharge input of the control element and a summing node is connected to one or more evaluation trees and to the control element output via an inverter. The inverter is connected to an override circuit that forces the output of the control element to a state opposite the precharge state until the control signal has ended. The output of the control element then assumes a state corresponding to the precharge state until an evaluation occurs. The control element output thus produces a window signal indicating the interval between the end of the control signal and the evaluation.

Abstract: A register file is often used within integrated circuitry to temporarily hold data. Sometimes this data needs to be retained within the register file for a period of time, such as when there is a stall operation. Conventional register files have utilized a hold multiplexor to perform such a stall operation. The multiplexor however inserts a delay that is undesirable in high performance integrated circuitry. The multiplexor is replaced with a tri-state inverter coupled to the global bit line of the register file, which minimizes this additional delay from the register file data access time.

Abstract: A register-file bit read apparatus includes a decoder operable to receive a number of address-bit signals and responsively assert a select signal on one of M select lines. Each select line corresponds to a respective one of M register-file cells. The apparatus also includes a multiplexer having Q output nodes and M selectors. Each selector is coupled to one of the select lines and that select line's corresponding register-file cell. The selectors are in Q groups, each coupled to a respective one of the multiplexer's output nodes. The apparatus also includes an output logic gate having Q inputs, coupled to respective ones of the multiplexer output nodes. The multiplexer includes Q pull-ups, each of which is coupled to a respective one of the multiplexer output nodes and is operable to drive its multiplexer output node responsive to one of the address-bit signals.

Abstract: A bit-read apparatus includes a first decoder and N multiplexers, each having Q output nodes and Q pull-ups coupled thereto. Respective multiplexers have M selectors coupled to N×M respective select lines and register-file cells. The selectors are in Q groups coupled to respective output nodes. Each multiplexer has a logic gate with inputs coupled to respective multiplexer output nodes. A second decoder is coupled to an N+1th multiplexer having R output nodes and R pull-ups coupled thereto. The N+1th multiplexer also has N selectors, coupled to respective select lines of the second decoder and respective output logic gates of the N multiplexers. The N selectors are in R groups coupled to the R nodes. An output logic gate for N+1th multiplexer has R inputs coupled respectively to the R nodes. Each pull-up of the multiplexers drives its respective multiplexer output node responsive to an address-bit signal.

Abstract: A memory array includes a storage unit with a number of sections and decoders coupled to respective ones of the sections for decoding an N-bit address signal and responsively asserting a signal on one of the word lines selected by the address signal. Local clock buffers are coupled to respective ones of the decoders for receiving a clock signal and an address signal including M most-significant bits of the N-bit address signal and generating respective timing signals. The decoders receive the timing signal from their respective local clock buffers. Each decoder is operable to alternately precharge and evaluate the N-bit address signal responsive to phases of the timing signal. Each local clock buffer is operable, responsive to a state of the M bits of the address signal, for selecting between holding its timing signal in a deasserted state and enabling its timing signal to follow the clock signal.

Abstract: A structure and method are provided which reduce memory cell size by forming self-formed contacts and self-aligned source lines in the array. In one embodiment of the present invention, a plurality of self-aligned memory cells are formed in an array. Then, a first insulating layer is deposited on the array, and subsequently etched to form spacers on the sidewalls of each memory cell. Conductive plugs are then formed between adjacent spacers. Subsequently, a second insulating layer is deposited over the array. Finally, drain contacts are formed through the second insulating layer a first set of plugs. Other plugs form source lines for the array. Because the present invention provides a self-formed contact, only the second insulating layer is etched to establish contact between a metal bit line and an underlying diffused drain region. Thus, the present invention ensures appropriate isolation for each memory cell while reducing the area required for contact formation.

Abstract: A structure and method are provided which reduce memory cell size by forming self-formed contacts and self-aligned source lines in the array. In one embodiment of the present invention, a plurality of memory cells are formed in an array. Then, a first insulating layer is deposited on the array, and subsequently etched to form spacers on the sidewalls of each memory cell. Conductive plugs are then formed between adjacent spacers. Subsequently, a second insulating layer is deposited over the array. Finally, drain contacts are formed through the second insulating layer to a first set of plugs. Other plugs form source lines for the array. Because the present invention provides a self-formed contact, only the second insulating layer is etched to establish contact between a metal bit line and an underlying diffused drain region. Thus, the present invention ensures appropriate isolation for each memory cell while reducing the area required for contact formation.