Atmel Corporation

Sgs-thomson Microelectronics S.r.l.

Stmicroelectronics S.r.l.

Fabio Tassan Caser

Stefano Sivero

Lorenzo Bedarida

Simone Bartoli

Mauro Luigi Sali

Riccardo Riva Reggiori

Massimiliano Frulio

Giorgio Oddone

Marcello Cane

Corrado Villa

Marco Dallabora

Marco Defendi

Mauro Chinosi

Stefano Surico

Marco Passerini

Mirella Marsella

Monica Marziani

Marco Dellabora

Stefan Schippers

Donato Ferrario

Luca Figini

A flash memory device includes a flash memory array, a set of non-volatile redundancy registers, a serial interface, and testing logic coupled to the serial interface, the testing logic configured to accept a set of serial commands from an external tester; erase the array; program the array with a test pattern; read the array and compare the results with expected results to identify errors; determine whether the errors can be repaired by substituting a redundant row or column of the array, and if so, generate redundancy information; and program the redundancy information into the non-volatile redundancy registers.

Embedded architecture with serial interface for testing flash memories

A method and system for protecting a memory having a plurality of blocks from modification is disclosed. The method and system include providing a plurality of one time programmable (OTP) cells and OTP cell logic coupled with the OTP cells. An OTP cell of the plurality of OTP cells corresponds to a portion of a block of the plurality of blocks. The OTP cell allows modification of the portion of the block when the OTP cell is in a first state and permanently prevents modification of the portion of the block when the OTP cell is in a second state. The OTP cell logic uses the plurality of OTP cells to select the portion of the block as corresponding to the OTP cell. This portion of the block is write protected when the OTP cell is placed in the second state.

Flexible OTP sector protection architecture for flash memories

A precharge and evaluation circuit for a memory sense amplifier includes a first precharge-phase transistor having a source coupled to a power-supply potential, a gate coupled to a precharge control line, and a drain. A second precharge-phase transistor has a drain coupled to the drain of the first precharge-phase transistor, a source, and a gate coupled to the source through a feedback circuit. A first read-phase transistor has a source coupled to the power-supply potential, and a gate and drain coupled to a comparator. A second read-phase transistor has a drain coupled to the drain of the first read-phase transistor, a source coupled to the source of the second precharge-phase transistor, and a gate coupled to the source of the second read-phase transistor through a feedback circuit. A column decoder is coupled to the sources of the second precharge-phase and second read-phase transistors.

Precharge and evaluation phase circuits for sense amplifiers

A charge pump circuit for generating a plurality of voltages in excess of a supply voltage includes a first group of cascaded charge-pump stages, the input of a first charge pump stage in the first group being driven from the supply voltage. A first output stage has an input driven from the output of a last charge pump stage of the first group and an output coupled to a first voltage node. A second group of cascaded charge-pump stages is provided, the input of the first charge pump stage of the second group being driven from the output of the last charge pump stage of the first group. A second output stage has an input driven from the output of the last charge pump stage in the second group and an output coupled to a second voltage node.

Charge pump for generation of multiple output-voltage levels

A system and method for reducing soft-writing in a multilevel flash memory during read or verify includes a memory cell. A first and second reference cells are coupled to the memory cell and are configured to receive a first and a second voltage. A current comparison circuit is coupled to the first and second reference cells and to the memory cell and is configured to compare current flow through the memory cell with current flow through the first and second reference cells, and to determine whether the memory cell holds a first range of values while the first reference cell receives the first voltage, and if the memory cell does not hold the first range of values, to determine whether the memory cell holds a second range of values while the second reference cell receives the second voltage, thereby reducing soft-writing during the read operation.

Method and system for reducing soft-writing in a multi-level flash memory

A method and system for providing a multi-bank memory is described. The method and system include providing a plurality of banks. Each of the plurality of banks includes at least one array including a plurality of memory cells and analog sensing circuitry. The method and system further include providing common digital sensing circuitry coupled with the plurality of banks.

Method and system for providing sensing circuitry in a multi-bank memory device

A memory device generates a select voltage and an unselect voltage on bit lines and generates a bit line select voltage having a magnitude less than the unselect voltage so that the application of the bit line select voltage to a gate of a transistor receiving the select voltage causes the transistor to conduct, and the application of the bit line select voltage to a gate of a transistor receiving the unselect voltage biases the transistor off.

Adaptive gate voltage regulation

An erase-verify method for a NAND flash memory includes a serial double-step erase verify. A verify operation is performed on cells in the unit connected to even word lines by biasing all the even word lines at the read voltage value used in read mode, and by biasing all the odd word lines at the pass voltage value used in read mode of the selected unit. A verify operation is performed on the cells connected to odd word lines by biasing all the odd word lines at the read voltage value used in read mode and by biasing the all even word lines at the pass voltage value used in read mode of the selected unit. Verifying the odd and even word lines may be performed in either order.

Erase verify method for NAND-type flash memories

Aspects for programming a nonvolatile electronic device include performing an initial verify step of a programming algorithm with an initial type of reference voltage value, and performing one or more subsequent verify steps in the programming algorithm with a second type of reference voltage value. Further included is utilizing a read reference voltage for the initial verify step, wherein desired programming is ensured for a cell that falls out of ideal distribution.

Method and system for a programming approach for a nonvolatile electronic device

An improved method and device for column decoding for flash memory devices utilizes a burst page with a length greater than the length of a logical page. When a misalignment of an initial address occurs, valid reads across logical page boundaries are possible. The memory device enters the wait state only when a read crosses a burst page boundary. This minimizes the amount of time in which the memory device enters the wait state. In the preferred embodiment, this is achieved with a different management of the control signals that feed the third level of a three-level decoding stage column decoder. Changes to the architecture or in the number of column decoder selectors are not required. The memory access time during synchronous reads is thus improved.

Column decoding architecture for flash memories

A system and method for preserving an error margin for a non-volatile memory that includes a memory cell, a reference cell coupled to a reference current mirror configured to mirror current through the reference cell. The system comprises a memory current mirror coupled to the memory cell and configured to mirror current through the memory cell. A sense amplifier has a first and a second input. The first input is coupled to the reference current mirror and the second input is coupled to the memory current mirror. The sense amplifier is configured to compare a voltage across the memory cell with a voltage across the reference cell.

System and method for preserving an error margin for a non-volatile memory

An n-channel MOS transistor negative-voltage charge pump is disclosed in which the bulks of the n-channel MOS transistors are biased in such a manner as to prevent turning on the parasitic bipolar transistor inherent in the CMOS environment of the charge pump structure.

Negative charge pump with bulk biasing

A voltage down-converter system, with a stand-by mode and an active mode, for a memory device with the following components. A charge node is configured to receive a charge. A first transistor has a first gate and the first transistor is configured to supply a load current to the memory device. A first switch is coupled to the charge node and the first gate, the first switch being configured to apply the charge in the charge node to the first gate during transition from stand-by to active modes. A second transistor is coupled to the first gate and configured to bias the first transistor to an inactive state during stand-by mode. A second switch is coupled to the first gate and the second transistor, the second switch being configured to apply a voltage difference at the second transistor to the first gate during the stand-by mode.

System for controlling the stand-by to active and active to stand-by transitions of a VCC regulator for a flash memory device

The invention relates to a row decoding circuit for an electrically programmable and erasable semiconductor non-volatile storage device of the type which includes a matrix of memory cells laid out as cell rows and columns and is divided into sectors, said circuit being input row decode signals and supply voltages in order to drive an output stage incorporating a complementary pair of high-voltage MOS transistors of the pull-up and pull-down type, respectively, which are connected to form an output terminal connected to the rows of one sector of the matrix, characterized in that a MOS transistor of the P-channel depletion type with enhanced gate oxide is provided between the output terminal and the pull-down transistor. The control terminal of the depletion transistor forms a further input of the circuit.

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Arcore, Italy

Fabio Tassan Caser