摘要:
To overcome these problems, the present invention generates two window strobes and uses the two window strobes to determine if skew between two signals meets predetermined criteria. One of the window strobes is used to test one of the signals, and the other window strobe is generated relative to the first window strobe. The second window strobe tests the other signal (or signals, if they are data signals). From the tests of the two window strobes, it can be determined if the skew between the first and second signals meets predetermined criteria. In particular, the two window strobes are placed relative to each other and to the signals being tested in such a way that when both window strobes indicate passing conditions, skew between the two signals is guaranteed.
摘要:
A method for testing the data strobe window (DQS) and data valid window (tDV) of a memory device (e.g., a DDR-type memory device) using the window strobe of a testing system.
摘要:
A SDRAM. The SDRAM including: at least one bank of DRAM cells; the SDRAM operable to a first specification defined by a first clock frequency, a first write recovery time and a first time interval for precharge to row address strobe; and means for programming the SDRAM operable to a second specification defined by a second clock frequency, a second write recovery time and a second time interval for precharge to row address strobe.
摘要:
Disclosed is a flexible command multiplication scheme for the built-in-self test (BIST) of a high-speed embedded memory array that segments BIST functionality into remote lower-speed executable instructions and local higher-speed executable instructions. A stand-alone BIST logic controller operates at a lower frequency and communicates with a command multiplier using a low-speed BIST instruction seed set. The command multiplier uses offset or directive registers to drive a logic unit or ALU to generate “n” sets of CAD information which are then time-multiplexed to the embedded memory at a speed “n” times faster than the BIST operating speed.
摘要:
A Defect Leakage Screen Test apparatus and method is introduced to eliminate or reduce steps in the failure analysis process of memory devices, such as DRAM cells, or to eliminate the necessity for the application of a physical failure analysis on the memory device. Special single bit failures due to leakage current, junction current, or threshold leakage current, are characterized by varying the p-well voltage of the memory device during the read operation of the test. The p-well voltage is varied with a test code Initial Program Load (IPL). Additional logic is provided on the memory IC to decode the IPL logic signals. In order to perform the p-well varying test, the memory device is provided with the following: IPL decoding logic; a reference voltage generator; an IPL voltage reference multiplexor; a p-well voltage feed-back circuit; and a differential amplifier circuit.
摘要:
A DDR DRAM having a test mode and an operational mode and a method for testing the DDR DRAM. The method includes in the order recited: (a) placing the DDR DRAM in test mode; (b) issuing a band activate command to select and bring up a wordline selected for write of the DDR DRAM; (c) writing with auto-precharge, a test pattern to cells of the DDR DRAM; (d) repeating steps (b) and (c) until all wordlines for write have been selected; (e) issuing a bank activate command to select and bring up a wordline selected for read of the DDR DRAM; (f) reading with auto-precharge, the stored test pattern from cells of the DDR DRAM; and (g) repeating steps (c) and (f) until all wordlines for read have been selected.
摘要:
A Schottky barrier diode comprises a doped guard ring having a doping of a second conductivity type in a semiconductor-on-insulator (SOI) substrate. The Schottky barrier diode further comprises a first-conductivity-type-doped semiconductor region having a doping of a first conductivity type, which is the opposite of the second conductivity type, on one side of a dummy gate electrode and a Schottky barrier structure surrounded by the doped guard ring on the other side. A Schottky barrier region may be laterally surrounded by the dummy gate electrode and the doped guard ring. The doped guard ring includes an unmetallized portion of a gate-side second-conductivity-type-doped semiconductor region having a doping of a second conductivity type. A Schottky barrier region may be laterally surrounded by a doped guard ring including a gate-side doped semiconductor region and a STI-side doped semiconductor region. Design structures for the inventive Schottky barrier diode are also provided.
摘要:
A DDR DRAM having a test mode and an operational mode and a method for testing the DDR DRAM. The method includes in the order recited: (a) placing the DDR DRAM in test mode; (b) issuing a bank activate command to select and bring up a wordline selected for write of the DDR DRAM; (c) writing with auto-precharge, a test pattern to cells of the DDR DRAM; (d) repeating steps (b) and (c) until all wordlines for write have been selected; (e) issuing a bank activate command to select and bring up a wordline selected for read of the DDR DRAM; (f) reading with auto-precharge, the stored test pattern from cells of the DDR DRAM; and (g) repeating steps (e) and (f) until all wordlines for read have been selected.