Abstract: A method of testing a memory cell includes generating a logic low signal, generating a logic high signal, reducing the logic high signal to a level corresponding to the logic low signal plus an offset to produce a reduced logic high signal, providing the logic low signal and the reduced logic high signal to a memory cell, allowing the memory cell to achieve a memory state, and testing the memory cell to determine if the memory state is an expected memory state. A memory array has an array of memory blocks, a write select circuit to provide write data to the array of memory blocks, and a data retention test circuit to reduce write data having a level corresponding to a logic high to a level corresponding to a logic low plus an offset.

Abstract: A method of testing a memory cell includes generating a logic low signal, generating a logic high signal, reducing the logic high signal to a level corresponding to the logic low signal plus an offset to produce a reduced logic high signal, providing the logic low signal and the reduced logic high signal to a memory cell, allowing the memory cell to achieve a memory state, and testing the memory cell to determine if the memory state is an expected memory state. A memory array has an array of memory blocks, a write select circuit to provide write data to the array of memory blocks, and a data retention test circuit to reduce write data having a level corresponding to a logic high to a level corresponding to a logic low plus an offset.

Abstract: A memory cell array employs “source-biasing”, wherein a bias voltage is applied to the sources of one or more FETs within a memory cell to reduce their “off” state sub-threshold leakage currents. The source-bias voltage is selectively switched between a small positive bias voltage for “off” FETs, and ground for FETs which are being read. A plurality of source-bias circuits provides the selectively switched bias voltages to the memory cells in the array.

Abstract: A memory cell array employs “source-biasing”, wherein a bias voltage is applied to the sources of one or more FETs within a memory cell to reduce their “off” state sub-threshold leakage currents. The source-bias voltage is selectively switched between a small positive bias voltage for “off” FETs, and ground for FETs which are being read. A plurality of source-bias circuits provides the selectively switched bias voltages to the memory cells in the array.

Abstract: Static read/write memory structures are provided that include predetermined latent-state patterns which can be retrieved with a latent-state retrieve process that differs somewhat from a conventional write process. The patterns are realized with threshold-voltage differences and they significantly enhance flexibility of memory allocation without increasing memory area nor significantly altering conventional read/write processes.

Abstract: A static Random Access Memory (RAM) has a sense enable circuit. A user-determinable number of timing cells produces a timing bit line output in response to a wordline enable input. A sense timing control circuit is triggered by the timing bit line output. The sense timing control circuit produces a sense enable signal for enabling a sensing amplifier to read the logic state of memory cells in communication with the sensing amplifier. A user can change the number of timing cells to optimize operation.

Abstract: A static Random Access Memory (RAM) has a sense enable circuit. A user-determinable number of timing cells produces a timing bit line output in response to a wordline enable input. A sense timing control circuit is triggered by the timing bit line output. The sense timing control circuit produces a sense enable signal for enabling a sensing amplifier to read the logic state of memory cells in communication with the sensing amplifier. A user can change the number of timing cells to optimize operation.

Abstract: A method and apparatus for measuring threshold voltages associated with the EEPROM portion of a non-volatile DRAM (NVDRAM) memory cell. The DRAM node of the NVDRUM cell is charged to a high potential and allowed to discharge through the EEPROM transistor. Since the gate of the EEPROM is tied to the DRAM node, the DRAM node voltage, which is also the EEPROM gate-to-source voltage, will, if the NVDRAM is left alone, drop until the EEPROM transistor shuts off. The EEPROM gate-to-source voltage at any point in time along this discharge path is measured through an iterative process. First, timing signals are adjusted to specify the point in time at which the EEPROM voltage is to be measured. Then, during each iteration, the EEPROM voltage is charged up and allowed to the discharge. At the point in time along the discharge path specified by the timing signals, a reference voltage is compared with the EEPROM voltage to determine if the reference voltage is above or below the EEPROM voltage.

Abstract: In a non-volatile DRAM (NVDRAM) memory device comprised of NVDRAM cells, each comprising a DRAM cell and an EEPROM cell, a method and apparatus for the page recall of data whereby the page recall start address may be specified by the user through the memory device's external control pins. A page of memory cells is defined as all of the memory cells connected to a single word line. During any recall operation, data are recalled from EEPROM to DRAM in only one memory cell per bit line. The externally specified page recall start address is input onto an external pad. It is then transmitted through an address selector circuit into the inputs of a counter circuit. The outputs of the counter circuit serve as the page recall start address, which reenters the address selector circuitry to be transmitted to address decoding circuitry.

Abstract: A circuit for enabling off-chip measurement of an on-chip generated reference voltage and for effectuating the memory margin testing of nonvolatile memory cells in wells of a CMOS integrated circuit chip. The circuit is configured to selectively couple off-chip voltages of positive and negative potential to nodes on the chip while avoiding undesired forward biasing of p-n junctions. Control is initiated by varying the functions the input pads perform.