Abstract: A memory device is provided including memory cells that are capable of switching between at least two states, where the threshold of a sense signal for detecting the current state depends on a data content of the memory cell. Parallel to a user data block, a primary control word including a predetermined number of bits of a first state is stored in a check section of the cell array. The check section is read by applying sense signals of different amplitudes, where in each case a secondary control word is obtained. By checking in each secondary control word the number of bits of the first state, the margins of the current sense signal amplitude towards the sense window limits may be checked and the sense signal amplitude may be adapted permanently to a sense window drift, so as to enhance the reliability of the memory device.

Abstract: A memory device including a cell array is disclosed. One embodiment includes a plurality of memory cells, wherein each memory cell is capable of showing at least two distinguishable states, a programmable read voltage source adapted to supply an alterable read voltage and a test control unit. The test control unit includes a voltage control unit that is capable of controlling the read voltage source, a counter unit that is capable of counting the memory cells exhibiting a predetermined state and an analysis unit that is capable of rating a currently determined number of memory cells exhibiting a predetermined state.

Abstract: A memory device is provided including memory cells that are capable of switching between at least two states, where the threshold of a sense signal for detecting the current state depends on a data content of the memory cell. Parallel to a user data block, a primary control word including a predetermined number of bits of a first state is stored in a check section of the cell array. The check section is read by applying sense signals of different amplitudes, where in each case a secondary control word is obtained. By checking in each secondary control word the number of bits of the first state, the margins of the current sense signal amplitude towards the sense window limits may be checked and the sense signal amplitude may be adapted permanently to a sense window drift, so as to enhance the reliability of the memory device.

Abstract: A method includes an initial process of selecting a memory cell within the memory array and an operating condition under which the memory cell is to be tested. The memory cell is tested under the specified operating condition, and a measured response obtained therefrom. Based upon the measured response, a determination is made as to whether the memory cell passes or fails a predetermined criterion. The pass/fail result is communicated to a counter that is integrated on-chip with the memory array, the counter operable to accumulate a total number of pass or fail results supplied thereto. The aforementioned processes are repeated for at least one different memory cell, whereby the new memory cell is tested under the aforementioned operating conditions. Subsequently, a data value representing the accumulated number of pass or fail results is output from the on-chip counter.

Abstract: A method for conducting programming and erasure of charge-trapped memory devices includes: conducting at least one program/erase cycle of a charge-trapped memory device on the basis of a given threshold voltage of the charge-trapped memory device as a reference point; determining a wear-level of the erasing procedure; shifting the reference point according to a result of the determination of the wear-level; conducting one or more program/erase cycle on the basis of the shifted threshold; and conducting read and verify operations on the basis of the shifted threshold.

Abstract: A method includes an initial process of selecting a memory cell within the memory array and an operating condition under which the memory cell is to be tested. The memory cell is tested under the specified operating condition, and a measured response obtained therefrom. Based upon the measured response, a determination is made as to whether the memory cell passes or fails a predetermined criterion. The pass/fail result is communicated to a counter that is integrated on-chip with the memory array, the counter operable to accumulate a total number of pass or fail results supplied thereto. The aforementioned processes are repeated for at least one different memory cell, whereby the new memory cell is tested under the aforementioned operating conditions. Subsequently, a data value representing the accumulated number of pass or fail results is output from the on-chip counter.