Abstract:
An apparatus and method for testing memory cells comprising coupling a first and a second memory cell to a first and a second bit lines, respectively, reading data from the first and second memory cells through the first and second bit lines, and comparing the voltage levels of the first and second bit lines.
Abstract:
A circuit and method are provided for stress-testing EEPROMS by incrementally selecting and deselecting word lines. The circuit of the invention comprises a memory cell array, a set of decoders for decoding a memory address bus and controlling word lines for the memory cell array, a control circuit, and a shift register driven by the control circuit. Each bit of the shift register has the capability of overriding a group of one or more of the decoders. When the initiation signal is received by the control circuit, a state control bit is set high and is clocked through the shift register. The high bit overrides successive groups of decoders as it is shifted through the shift register, until all word lines in the memory cell array are selected. After the stress test has been performed, the state control bit is returned to zero and is cycled through the shift register on successive clock cycles, incrementally deselecting groups of word lines until all word lines are deselected.
Abstract:
It discloses novel BIST controller which detects single port faults and inter-port shorts in multi-port random access memories. The algorithm performs a conventional single-port test such as MARCH or SMARCH on one port of the memory and performs an inter-port test on all other ports. The algorithm does not impose any extra test time and requires the addition of only a few gates to a conventional single-port BIST controller, independently of the size of the memory.
Abstract:
A memory controller includes a generator circuit configured to generate a predetermined pattern of data, an address input, and a memory interface circuit. The memory interface circuit is configured to write the predetermined pattern of data to a memory at an address identified in the address input. The memory interface circuit is further configured to read a stored pattern of data from the memory at the address. The memory controller further includes an integrity checker circuit configured to compare the predetermined pattern of data and the stored pattern of data and identify an error of the memory based upon the comparison.
Abstract:
The invention relates to measures by which means the efficacy of the high-voltage (HV) screening of integrated circuits comprising a memory structure and a word decoder can be significantly improved. A plurality of memory cells (11) of the memory structure (1) are respectively collected together to form one word. The outputs of the word decoder (2) are respectively connected to a word of the memory structure (1) by means of word lines (12). Said word decoder (2) first determines the complements of address bits from adjacent address bits by means of a logical circuit element. For each word of the memory structure (1), the word decoder (2) then determines a word line signal equivalent to 0 or 1, by means of the logical circuit element and from the address bits and the complements thereof, and can thus isolate a word of the memory structure (1) for an access, i.e. for a reading process and/or a writing process. During high-voltage screening, the supply voltage is increased for different circuit conditions designated as screening vectors. According to the invention, the logical circuit element comprises optionally activatable means for equating the address bits with the complements thereof, in such a way that a test mode can be activated in order to generate screening vectors. According to this mode, all address bits are equated and the complements of the address bits are likewise equated with the address bits.
Abstract:
A RAMBUS dynamic random access memory (40) includes a test control circuit (44) that selectively couples a row address latch to either a row sense control signal or a CAD control signal. In a normal operating mode, the test control circuit couples the row address latch (26) to the row sense control signal so that the row sense control signal both latches a row address and senses a row of memory cells corresponding to the latched address. Prior to conducting a core noise test, the test control circuit couples the row address latch to the CAD control signal so that the row address is latched by the CAD control signal, and the row sense control signal only functions during the core noise test to sense a row corresponding to the latched row. The memory also includes a multiplexer (48) that receives a time-multiplexed data/address bus and simultaneously couples a first part of the data/address bus to an internal data bus and a second part of the data/address bus to an internal address bus.
Abstract:
A Built-in Self Test (BIST) scheme for testing Random Access Memories (RAMs) is disclosed. This scheme is capable of testing either stand-alone or embedded RAMs. Furthermore testing algorithms to exploit this scheme in order to detect all Neighborhood Pattern Sensitive Faults (NPSFs) as well as all cell stuck-at and transition faults in the memory array, and also all single stuck-at faults in the address decoding or the sensing/writing circuitry, are given. The BIST circuitry includes a BIST Controller, a Test Pattern Generation (TPG) unit, a register (RWR) to read and write test data from/to the memory array and a BIST I/O circuitry. The BIST Controller controls the RAM during the test mode of operation while TPG generates the proper test patterns to test the RAM. Test patterns are used to fulfill the RWR register. Since, in the proposed scheme the cells of RWR are connected directly to the sense amplifiers and write buffers of the sensing/writing circuitry, test data can be written to the cells of a word line in parallel while multiple word lines can be written with the same test data in successive write sessions. In addition various methods are given to evaluate the data retrieved in RWR from the memory array, in order to detect and locate possible faults. Finally, the BIST I/O is capable of storing test information concerning the location of a malfunction in the RAM and outputting this information to the external environment via an integrated circuit I/O port or in collaboration with a TAP controller.
Abstract translation:公开了一种用于测试随机存取存储器(RAM)的内置自测(BIST)方案。 该方案能够测试独立或嵌入式RAM。 此外,测试算法利用此方案以检测所有邻域模式敏感故障(NPSF)以及存储器阵列中的所有单元卡住和转换故障,以及地址解码或传感中的所有单一卡住故障 /写电路。 BIST电路包括BIST控制器,测试模式产生(TPG)单元,用于从/到存储器阵列读取和写入测试数据的寄存器(RWR)以及BIST I / O电路。 BIST控制器在测试操作模式期间控制RAM,而TPG生成适当的测试模式以测试RAM。 测试模式用于完成RWR寄存器。 由于在所提出的方案中,RWR的单元直接连接到感测/写入电路的读出放大器和写入缓冲器,所以可以将测试数据并行地写入字线的单元,同时可以写入多个字线 连续写入会话中的相同测试数据。 此外,给出了从存储器阵列中评估在RWR中检索的数据的各种方法,以便检测和定位可能的故障。 最后,BIST I / O能够存储关于RAM中的故障位置的测试信息,并通过集成电路I / O端口或与TAP控制器协作将该信息输出到外部环境。
Abstract:
One embodiment provides a runtime programmable system which comprises methods and apparatuses for testing a multi-port memory device to detect a multi-port memory fault, in addition to typical single-port memory faults that can be activated when accessing a single port of a memory device. More specifically, the system comprises a number of mechanisms which can be configured to activate and detect any realistic fault which affects the memory device when two simultaneous memory access operations are performed. During operation, the system can receive an instruction sequence, which implements a new test procedure for testing the memory device, while the memory device is being tested. Furthermore, the system can implement a built-in self-test (BIST) solution for testing any multi-port memory device, and can generate tests targeted to a specific memory design based in part on information from the instruction sequence.