Stmicroelectronics S.r.l.

Stmicroelectronics International N.v.

Carolina Selva

Danilo Rimondi

Cosimo Torelli

Rita Zappa

Ashish Kumar

Donatella Brambilla

Giovanni Mastrodomenico

An embodiment of a memory device of SRAM type is proposed. The memory device includes a plurality of memory cells each for storing a first logic value represented by a first reference voltage or a second logic value represented by a second reference voltage. Each memory cell includes a bistable latch&#x2014;having a main terminal, a complementary terminal, a set of main storage transistors for maintaining the main terminal at the reference voltage corresponding to the stored logic value, and a set of complementary storage transistors to maintain the complementary terminal at the reference voltage corresponding to the complement of the stored logic value&#x2014;a main access transistor and a complementary access transistor for accessing the main terminal and the complementary terminal, respectively. The memory device may further include biasing means for modifying a value of a threshold voltage of at least one of the main transistors to a first threshold voltage value or to a second threshold voltage value and for modifying a threshold voltage value of at least one of the complementary transistors to the second threshold voltage value or to the first threshold voltage value during a write operation of the first logic value or of the second logic value, respectively, in the memory cell.

Dynamically configurable SRAM cell for low voltage operation

A static random access memory (SRAM) device includes a memory array of a plurality of memory cells, a controller that receives an external clock signal formed by a succession of external pulses and generates an internal clock signal formed by a succession of internal pulses, and a driving circuit that receives the internal clock signal. The controller is operable in a first mode, wherein the controller generates, for each external pulse, a corresponding internal pulse and the controller controls the driving circuit so that the driving circuitry carries out one access to the memory array for each internal pulse. The controller is further operable in a second mode, wherein the controller generates, for each external pulse, a pair of internal pulses, and the controller controls the driving circuitry so that, for each pair of internal pulses, the driving circuitry writes a first data item in a set of memory cells, and then reads the set of memory cells, so as to acquire a second data item.

SRAM memory device and testing method thereof

An electronic device for executing a reliability test. Such an electronic device includes a circuit for implementing a functionality of the electronic device, and testing circuit for executing a test of the functional circuit including a plurality of test operations on the functional circuit. The testing circuit returns an indication of a result of each test operation. In an embodiment, the electronic device further includes control circuit for causing the testing circuit to reiterate the test, monitoring circuit for monitoring the result of each test operation to detect a failure of the test operation, and storage circuit for storing failure information indicative of temporal characteristics of each failure.

Reliability test with monitoring of the results

A method for testing a memory device. The memory device includes a matrix of memory cells having a plurality of rows and columns; the matrix includes a plurality of rows of operative memory cells each one for storing a variable value and at least one row of auxiliary memory cells each one storing a fixed value. The memory device further includes writing circuitry for writing selected values into the operative memory cells, and reading circuitry for reading the values being stored from the operative or auxiliary memory cells. The method includes reading output values from the row of auxiliary memory cells, determining a malfunctioning of the memory device in response to a missing match of the output values with the fixed values, determining a cause of the malfunctioning according to a pattern of reading errors between the output values and the corresponding fixed values, and providing a signal indicative of the cause of the malfunctioning.

Integrated solution for identifying malfunctioning components within memory devices

An embodiment of a memory device of SRAM type integrated in a chip of semiconductor material is proposed. The memory device includes a plurality of memory cells each for storing a binary data having a first logic value represented by a first reference voltage or a second logic value represented by a second reference voltage. Each memory cell includes a bistable latch&#x2014;having a main terminal, a complementary terminal, a set of field effect main storage transistors coupled to the main terminal for maintaining the main terminal at the reference voltage corresponding to the stored logic value or to a complement thereof, a set of field effect complementary storage transistors coupled to the complementary terminal for maintaining the complementary terminal at the reference voltage corresponding to the complement of the logic value associated with the main terminal&#x2014;and a field effect access transistor for accessing the main terminal. The chip includes an isolated well, the access transistor and at least one of the complementary storage transistors being formed in the isolated well.

5T SRAM memory for low voltage applications

An embodiment of a memory device includes a plurality of memory cells; each memory cell includes a latch adapted to store an information bit. Said latch includes a first logic gate including a first input terminal and a first output terminal and a second logic gate including a second input terminal and a second output terminal. Said first input terminal is connected to said second output terminal and said first output terminal is connected to said second input terminal. The memory device further includes reading and writing means adapted to perform a read operation or a write operation of the information bit. Said first logic gate includes a pull-up branch coupled between a terminal for providing a supply voltage and the first output terminal, and a pull-down branch coupled between the first output terminal and a terminal for providing a reference voltage. Said second logic gate includes a pull-up branch coupled between a terminal for providing the supply voltage and the second output terminal, and a pull-down branch coupled between the second output terminal and a terminal for providing the reference voltage. Said memory device includes variation means adapted to selectively vary a gain factor of at least one between the pull-down branch and the pull-up branch of said first logic gate and second logic gate depending on the operation performed by the reading and writing means.

Adjustable impedance SRAM memory device

A method is for making an integrated circuit with built-in self-test. The method includes forming at least one nonvolatile read only memory (ROM) to store ROM code and forming a logic self-test circuit to verify a correct functioning of the at least one nonvolatile ROM. Moreover, the method includes defining, in the logic self-test circuit, a logic self-test core to process the ROM code and to generate a flag based upon a control signature and defining, in the logic self-test circuit, a nonvolatile storage block, coupled to the logic self-test core, to store the control signature. Furthermore, the method includes writing the ROM code to the at least one nonvolatile ROM and writing the control signature to the nonvolatile storage block, during a same fabrication step.

Process and system for the verification of correct functioning of an on-chip memory

A self diagnosis (BISD) device for a random memory array, preferably integrated with the random access memory, executes a certain number of predefined test algorithms and identifies addresses of faulty locations. The BISD device recognizes certain fail patterns of interest and generates bit-strings corresponding to them. In practice, the BISD device may diagnose memory arrays and allow the identification of defects in the production process that affect a new technology during its learning phase, thus accelerating its maturation.

Built-in self diagnosis device for a random access memory and method of diagnosing a random access

A built-in self-test and self-repair structure (BISR) of memory arrays embedded in an integrated device includes at least a test block (BIST) programmable to execute on a respective memory array of the device any of a certain number of test algorithms, and a self-repair block that includes a column address generator processing the faulty address information for allocating redundant resources of the tested memory array. The BISR may further include a redundancy register on which final redundancy information is loaded at each power-on of the device and control logic for managing data transfer from external circuitry to the built-in self-test and self-repair structure (BISR) and vice versa. The BIST structure serves any number of embedded memory arrays even of different types and sizes.

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Cologno Monzese, Italy

Carolina Selva