Abstract: As part of anti-fuse circuitry for a memory device, a preferred exemplary embodiment of the current invention provides a direct connection between an anti-fuse and a contact pad used to provide voltage to that anti-fuse. The contact pad also serves as a voltage source for at least one other part of the memory device. At least one circuit coupled to the anti-fuse is temporarily isolated from it in the event that a voltage present at the pad would damage the circuit or cause the circuit to improperly read the status of the anti-fuse. The contact pad is available during a probe stage of the in-process memory device, but once the device is packaged, access to that contact pad is prevented. At the back end of the production process, the anti-fuse may be accessed through a second pad, whose electrical communication with the anti-fuse is regulated.

Abstract: An integrated circuit includes a first external pin and an input buffer connected to the first external pin. The input buffer includes an output terminal and a first test mode input terminal adapted to disable the output terminal in response to a first test mode signal. A method for testing an integrated circuit, the integrated circuit including a first external pin and an input buffer, includes providing a first external input signal to the first external pin at a first specified time, and disabling the input buffer at a second specified time after the first specified time.

Abstract: As part of anti-fuse circuitry for a memory device, a preferred exemplary embodiment of the current invention provides a direct connection between an anti-fuse and a contact pad used to provide voltage to that anti-fuse. The contact pad also serves as a voltage source for at least one other part of the memory device. At least one circuit coupled to the anti-fuse is temporarily isolated from it in the event that a voltage present at the pad would damage the circuit or cause the circuit to improperly read the status of the anti-fuse. The contact pad is available during a probe stage of the in-process memory device, but once the device is packaged, access to that contact pad is prevented. At the backend of the production process, the anti-fuse may be accessed through a second pad, whose electrical communication with the anti-fuse is regulated.

Abstract: A method, apparatus, and system are provided for implementing a zero-enabled fuse system. An apparatus includes a first set of fuses for activating a first memory portion, and a second set of fuses for activating a second memory portion. The apparatus also includes a controller to control an operation of the first and second set of fuses. The controller is adapted to determine whether a zero address memory location relating to the first memory portion is to be activated based upon an enable fuse. The controller is adapted to also perform a check to determine whether the second set of fuses has been previously activated.

Abstract: A power saving circuit disables input buffers for command and address signals during an auto-refresh of a DRAM. The input buffers are re-enabled at the end of the auto-refresh in a manner that does not cause spurious commands to be generated. The power saving circuit prevents spurious commands by biasing internal command signals to a “no operation” command whenever the input buffers for the command signals are disabled. The DRAM may also be placed in a mode in which it automatically transitions to a low power precharge mode at the end of the auto-refresh to further reduce power consumed by the DRAM.

Abstract: There is provided an input buffer circuit that, in one embodiment, includes an input buffer adapted to draw an operating current, a first buffer enabling circuitry operatively coupled to the input buffer and adapted to provide a first portion of the operating current to the input buffer, and second buffer enabling circuitry operatively coupled to the input buffer and adapted to provide a second portion of the operating current to the input buffer if the input buffer is expecting data, the second buffer enabling circuitry being adapted to be activated by a bias signal that is produced from an enable signal and a CLOCK signal.

Abstract: An isolation circuit includes a first pad adapted to receive a control signal and a second pad adapted to receive another signal. A third pad is coupled to a microelectronic die and a device is provided to transfer the other signal from the second pad to the third pad in response to the control signal.

Abstract: An apparatus and method using a reduced number of nonvolatile programming elements for enabling redundant memory blocks in a semiconductor memory is disclosed. A redundancy selection module may be configured using N fuses to configure and select 2N?1 repair modules. Programming fuses effectively separates the repair modules into two sets, those with an even address and those with an odd address. Each repair module contains fuses programmed with a selected address, such that the repair module may respond when an address input matches the selected address. However, the least significant bit is left out of the programming. As a result, repair modules in the even set respond to even addresses matching the selected address and repair modules in the odd set respond to odd addresses matching the selected address. Similar arrangements may be used to reduce the number of enable fuses and disable fuses required for each repair module.

Abstract: An apparatus and method using a reduced number of fuses for enabling redundant memory blocks in a semiconductor memory is disclosed. In one embodiment, a redundancy selection module may be configured using selection fuses, wherein each selection fuse selects a pair of repair modules. In another embodiment, a redundancy selection module may be configured using selection fuses, wherein each selection fuse may select a power of two (i.e., 1, 2, 4, 8, etc.) number of repair modules. Each repair module includes fuses programmed with a selected address, such that the repair module may respond when an address input matches the selected address. However, the Least Significant Bit (LSB) is uninvolved in the address programming. Instead, the LSB is compared to the values of the selection fuses. As a result, repair modules select a redundant memory block based on a combination of the selected address comparison and the separate LSB comparison.

Abstract: A method, apparatus, and system are provided for implementing a zero-enabled fuse system. An apparatus includes a first set of fuses for activating a first memory portion, and a second set of fuses for activating a second memory portion. The apparatus also includes a controller to control an operation of the first and second set of fuses. The controller is adapted to determine whether a zero address memory location relating to the first memory portion is to be activated based upon an enable fuse. The controller is adapted to also perform a check to determine whether the second set of fuses has been previously activated.

Abstract: A signal sharing circuit includes a first pad adapted to receive a signal and a first sharing device associated with a first microelectronic die. The first sharing device is adapted to selectively share the signal with at least a second microelectronic die on one side of the first microelectronic die in response to a first share control signal.

Abstract: A booting circuit, used during antifuse programming, that has a clamping circuit designed to prevent a programming voltage from being unnecessarily limited by other components in an integrated circuit. The booting circuit is connected between an external interface, such as a bond pad, and an internal line, and is activated when the programming voltage is being applied directly to the internal line (i.e., not through the external interface). When activated, the clamping circuit allows a suitable and sufficiently high voltage to be applied to the internal line to properly program the antifuses while also clamping the amount of voltage seen at the external interface.

Abstract: A lower current input buffer is used for waking up a plurality of higher-current buffers. The lower current buffer monitors a wake-up signal and, when present, enables the higher current buffers. A higher current buffer is used to detect the sleep mode and disable the higher current buffers. A delay circuit may be used to balance the propagation delay through the circuit.

Abstract: Circuitry is provided to allow early switching of input signals from a first configuration directed to blow a first anti-fuse to a second configuration directed to blow a second anti-fuse, yet still allow complete blowing of the first anti-fuse. Such circuitry may be applied to methods of repairing a memory device after testing. Data concerning available repair cells may be stored in at least one on-chip redundancy register.

Abstract: A preferred exemplary embodiment of the current invention concerns a memory testing process, wherein circuitry is provided on a chip to allow on-chip comparison of stored data and expected data. The on-chip comparison allows the tester to transmit in a parallel manner the expected data to a plurality of chips. In a preferred embodiment, at most one address—and only the column address—corresponding to a failed memory cell is stored in an on-chip register at one time, with each earlier failed addresses being cleared from the register in favor of a subsequent failed address. Another bit—the “fail flag” bit—is stored in the register to indicate that a failure has occurred. If the fail flag is present in a chip, that chip is repaired by electrically associating the column address with redundant memory cells rather than the original memory cells. Subsequently, the chip's register may be cleared and testing may continue.

Abstract: A method of monitoring the characteristics of a delay locked loop (DLL) in a memory device during a test mode is provided. The DLL generates an internal clock signal based on an external clock signal. The external and internal clock signals are normally synchronized. DLL constantly responds to variations in operating condition of the memory device to keep the external and internal clock synchronized. The method involves preventing the DLL from responding to a change in operating condition such as a change in the supply voltage of the memory device during a test mode.

Abstract: A method and apparatus for improving time between row address latching and column address latching (tRCD) by allowing the pull-up of the IO lines during a READ burst to end upon the firing of a column access signal rather than waiting for the next clock signal of the READ operation. A latch is set during the active command in order to set a node voltage which allows the IO pull-up signal to end upon the firing of the column access signal. The invention allows improvement in tRCD parameter, and allows digit line pairs to separate without unwanted line sharing with the IO lines prior to reading of the first bit of a data burst. The result is a more accurate and error-free read of a first bit of data during a READ sequence.

Abstract: A low-current input buffer is disclosed. The buffer uses self-biased N and P channel differential pairs with their outputs tied together. The self-biasing assists in reducing current consumption. The combination of N and P-channel differential pairs results in symmetry across a wide range of reference and supply voltages.

Abstract: A power saving circuit disables input buffers for command and address signals during an auto-refresh of a DRAM. The input buffers are re-enabled at the end of the auto-refresh in a manner that does not cause spurious commands to be generated. The power saving circuit prevents spurious commands by biasing internal command signals to a “no operation” command whenever the input buffers for the command signals are disabled. The DRAM may also be placed in a mode in which it automatically transitions to a low power precharge mode at the end of the auto-refresh to further reduce power consumed by the DRAM.

Abstract: In a memory device, an on-die register is provided that is configured to store a row address as well as a column address of a memory cell that fails a test. Storing the row address frees testing from being limited to activating at one time only rows related to a common redundant segment. Storing the row address also guides repair using segmented redundancy. As an addition or alternative, information may be stored in an anti-fuse bank that is designed to provide access to a redundant cell but has not yet enabled access to that cell. If the information stored in the anti-fuse bank relates to the failure of the redundant cell, such information may be used to avoid repairing with that redundant cell.