Abstract:
An electrically erasable and programmable non-volatile memory device comprises at least one memory sector (S1-S8) comprising an array of memory cells (MC) arranged in rows (WL0-WL255) and first-level columns (BL0-BL255), the first-level columns (BL0-BL255) being grouped together in groups of first-level columns each coupled to a respective second-level column (B1-B64), first-level selection means (2) for selectively coupling one first-level column for each group to the respective second-level column, second-level selection means (3,4) for selecting one of the second-level columns, first direct memory access test means (SW6) activatable in a first test mode for directly coupling a selected memory cell (MC) of the array to a respective output terminal (Oi) of the memory device, redundancy columns (RBL0-RBL3) of redundancy memory cells (RMC) for replacing defective columns (BL0-BL255) of memory cells (MC), and a redundancy control circuit (CAM1-CAM4,5-7,12,SW1-SW5,24) comprising defective-address storage means (CAM1-CAM4) for storing addresses of the defective columns (BL0-BL255) and activating respective redundancy columns (RBL0-RBL3) when the defective columns are addressed. The redundancy control circuit comprises second direct memory access test means (24) activatable in a second test mode together with the first direct memory access test means for directly coupling memory elements (AB0-AB7,GB) of the defective-address storage means (CAM1-CAM4) to respective second-level columns (B1-B64) of the array, whereby the memory elements of the defective-address storage means can be directly coupled to output terminals (Oi) of the memory device.
Abstract:
The invention concerns a method of avoiding disturbance during an erasing steps of an electrically programmable and erasable, semiconductor integrated non-volatile memory device, which comprises a matrix of memory cells divided into sectors. An operation of parallel erasing several sectors of the matrix as well as an operation of verifying the erasing of each sector in the matrix are carried out.
Abstract:
The invention concerns a method of avoiding disturbance during an erasing steps of an electrically programmable and erasable, semiconductor integrated non-volatile memory device, which comprises a matrix of memory cells divided into sectors. An operation of parallel erasing several sectors of the matrix as well as an operation of verifying the erasing of each sector in the matrix are carried out.