Abstract: An integrated circuit having a voltage protection circuit in electrical communication with an input buffer of the integrated circuit and a method for providing voltage protection to the input buffer. In one exemplary embodiment, the voltage protection circuit is an active device, such as a transistor, in electrical communication with an input node of the input buffer. When the active device actuates it provides a current path which limits a potential seen at the input buffer to a value less than an electrostatic discharge (ESD) potential. In one implementation the active device responds to a voltage which develops in response to current flow in an ESD circuit, and in a further implementation it responds to a gate to source potential during an ESD event. In both implementations the active device is actuated during an ESD event and is deactuated during normal operation of the circuit.

Abstract: An integrated circuit, including but not limited to a memory device, receives an externally provided voltage signal and selectively adjusts the timing of internal control signals. An external signal selects between two possible pre-determined delay paths. The delay paths are adjusted using fuse circuitry which can be programmed by the manufacturer prior to implementation by a user. The delay path adjustment feature is particularly applicable to adjusting output signal timing to allow the integrated circuit to be operated in an environment which requires slower communications speeds. The same integrated circuit, therefore, can also be implemented in an environment which allows for faster communications speeds.

Abstract: A method and apparatus is described for selectively adjusting control signal timing in a memory device as a function of the frequency of an externally applied clock signal. The memory device includes clock sensing circuitry that receives the clock signal and responsively produces a plurality of speed signals that transition a plurality of times corresponding in number to the frequency of the clock signal. The memory device also includes a control signal delay circuit that receives a memory command signal and the speed signals, and responsively produces a delayed control signal having a time delay from the command signal corresponding to the number of transitions of the speed signal value. Significantly, the control signal is generated during a period of the clock signal that immediately follows a period of the clock signal when the delay of the control signal delay circuit is set.

Abstract: A method and apparatus is described for selectively adjusting control signal timing in a memory device as a function of the externally applied system clock speed. The memory device includes clock sensing circuitry that receives the system clock signal and responsively produces a speed signal having a value corresponding to the frequency of the system clock signal. The clock sensing circuitry includes a plurality of series-connected time-delay circuits through which a signal derived from the system clock signal propagates. The clock sensing circuitry also includes a plurality of latch circuits, each coupled with a respective one of the time delay circuits and latching the value of the signal reaching the respective time delay circuit. The speed signal is then derived from these latched signal values, indicating through how many of the time-delay circuits the signal has propagated.

Abstract: A memory device is described which is operable in both a synchronous mode and a bus efficient mode (BE). Address and data register circuitry provide multiple propagation paths which can be selected based upon the operating mode and function performed. These features allow one memory device to be manufactured for multiple commercial applications. The address and data register circuitry have first and second paths, wherein the second paths are longer than the first paths. Control circuitry is provided to select the desired paths. During a synchronous and BE read operations, the first path of both the address and data register circuitry is selected. During BE write operations, the second path of the address register circuitry is selected. If the BE is operating in non-pipelined mode, the second path of the data register circuitry is selected.

Abstract: A memory device is described which is operable in both a synchronous mode and a bus efficient mode (BE). Address and data register circuitry provide multiple propagation paths which can be selected based upon the operating mode and function performed. These features allow one memory device to be manufactured for multiple commercial applications. The address and data register circuitry have first and second paths, wherein the second paths are longer than the first paths. Control circuitry is provided to select the desired paths. During a synchronous and BE read operations, the first path of both the address and data register circuitry is selected. During BE write operations, the second path of the address register circuitry is selected. If the BE is operating in non-pipelined mode, the second path of the data register circuitry is selected.

Abstract: A write driver circuit includes a drive circuit having a first drive node adapted to receive a first voltage, a second drive node, an input adapted to receive a data signal, and an output. The drive circuit couples the output to the first voltage node when the data signal has a first logic voltage, and couples the output to the second drive node when the data signal has a second logic voltage. A test circuit has an input adapted to receive a test mode signal, and an output coupled to the second drive node. The test circuit develops a first impedance between the second drive node and a second voltage source when the test mode signal is active, and develops a second impedance between the second drive node and the second voltage source when the, test mode signal is inactive.

Abstract: An integrated circuit having a voltage protection circuit in electrical communication with an input buffer of the integrated circuit and a method for providing voltage protection to the input buffer are disposed. In one exemplary embodiment, the voltage protection circuit is an active device, such as a transistor, in electrical communication with an input node of the input buffer. When the active device actuates it provides a current path which limits a potential seen at the input buffer to a value less than an electrostatic discharge (ESD) potential. In one implementation the active device responds to a voltage which develops in response to current flow in an ESD circuit, and in a further implementation it responds to a gate to source potential during an ESD event. In both implementations the active device is actuated during an ESD event and is deactuated during normal operation of the circuit.

Abstract: A method and apparatus is described for selectively adjusting control signal timing in a memory device as a function of the externally applied system clock speed. The memory device includes clock sensing circuitry that receives the system clock signal and responsively produces a speed signal having a value corresponding to the frequency of the system clock signal. The clock sensing circuitry includes a plurality of series-connected time-delay circuits through which a signal derived from the system clock signal propagates. The clock sensing circuitry also includes a plurality of latch circuits, each coupled with a respective one of the time delay circuits and latching the value of the signal reaching the respective time delay circuit. The speed signal is then derived from these latched signal values, indicating through how many of the time-delay circuits the signal has propagated.

Abstract: A method, apparatus and system for cost-effectively quantifying the likelihood of operational reliability problems includes a supply voltage configuration circuit and a test mode generation circuit. The test mode generation circuit and supply voltage configuration circuit, operating together in a test mode, provide selected supply voltages to selected circuit blocks of an integrated circuit. In non-test operation, the test mode generation circuit and the supply voltage configuration circuit are transparent to the operation of the tested integrated circuit.

Abstract: A memory device is described which is operable in both a synchronous mode and a bus efficient mode (BE). Address and data register circuitry provide multiple propagation paths which can be selected based upon the operating mode and function performed. These features allow one memory device to be manufactured for multiple commercial applications. The address and data register circuitry have first and second paths, wherein the second paths are longer than the first paths. Control circuitry is provided to select the desired paths. During a synchronous and BE read operations, the first path of both the address and data register circuitry is selected. During BE write operations, the second path of the address register circuitry is selected. If the BE is operating in non-pipelined mode, the second path of the data register circuitry is selected.

Abstract: An integrated circuit is described which includes a test mode circuit that allows a substrate of the integrated circuit to be forced to a voltage level dictated by an external connection during a test operation, and provides an improved substrate isolation from the external connection during non-test operations. Both n-channel transistor and p-channel transistor isolation circuit embodiments are described. An integrated circuit memory device is described which incorporated the test mode and isolation circuits. The external connection can be coupled to a negative voltage during non-test operation which is more negative than a threshold voltage below a substrate voltage without inadvertently coupling the external connection and substrate together.

Abstract: A semiconductor integrated circuit includes a biasing circuit connected to a plurality of memory cells via an access line. Each of the memory cells includes at least one switching device. The biasing circuit supplies a potential, having a value between a reference voltage and the threshold voltage of the switching device, to the access line for programming one of the memory cells to a logic low level.