Methods and systems for testing memory systems are disclosed. A refresh rate for a test system including a number of memory devices may be controlled based on estimated power scenario of a memory system design. In response to performance of a number of refresh operations on the memory devices and based on the refresh rate, one or more conditions of the test system may be monitored to generate estimated performance data for the memory system design.

Embodiments presented herein are directed to testing and/or debugging a memory device of a memory module (e.g., a dual in-line memory module (DIMM)) without having to remove the DIMM from a corresponding computing device and without having to interrupt operation of the computing device. A particular memory device (e.g., DRAM) may be identified for testing and/or debugging based on a failure message. However, the failure message may not identify a specific location or hardware of the module that caused the failure. Embodiments presented herein provide techniques to obtain data for analysis to determine and/or deliver a cause of the failure while reducing or eliminating downtime of the computing device. Test modes to do so may include a synchronous test mode, an asynchronous test mode, and an analog compare mode. A test mode may be selected based on the failure or a signal/function of the DRAM to be tested or debugged.

Embodiments presented herein are directed to testing and/or debugging a memory device of a memory module (e.g., a dual in-line memory module (DIMM)) without having to remove the DIMM from a corresponding computing device and without having to interrupt operation of the computing device. A particular memory device (e.g., DRAM) may be identified for testing and/or debugging based on a failure message. However, the failure message may not identify a specific location or hardware of the module that caused the failure. Embodiments presented herein provide techniques to obtain data for analysis to determine and/or deliver a cause of the failure while reducing or eliminating downtime of the computing device. Test modes to do so may include a synchronous test mode, an asynchronous test mode, and an analog compare mode. A test mode may be selected based on the failure or a signal/function of the DRAM to be tested or debugged.

The present disclosure provides a memory device, wherein: an address latch can output a block selection control signal according to a block selection enable signal; a test mode selection unit can output a test mode selection signal according to a test mode selection instruction signal; a block selection unit outputs a block selection signal according to a mode selection signal and a block selection enable signal; when the memory enters a first test mode according to the test mode selection signal, an output buffer disables some of the input/output ports, and sequentially outputs the first input/output data and the second input/output data through un-disabled the input/output ports. The memory device according to the present disclosure can occupy less input/output ports of a test machine.

A memory device to program a group of memory cells to store multiple bits per memory cell. Each bit per memory cell in the group from a page. After determining a plurality of read voltages of the group of memory cells, the memory device can read the multiple pages of the group using the plurality of read voltages. For each respective page in the multiple pages, the memory device can determine a count of first memory cells in the respective page that have threshold voltages higher than a highest read voltage, among the plurality of read voltages, used to read the respective page. The count of the first memory cells can be compared with a predetermined range of a fraction of memory cells in the respective page to evaluate the plurality of read voltages (e.g., whether any of the read voltages is in a wrong voltage range).

A memory device to program a group of memory cells to store multiple bits per memory cell. Each bit per memory cell in the group from a page. After determining a plurality of read voltages of the group of memory cells, the memory device can read the multiple pages of the group using the plurality of read voltages. For each respective page in the multiple pages, the memory device can determine a count of first memory cells in the respective page that have threshold voltages higher than a highest read voltage, among the plurality of read voltages, used to read the respective page. The count of the first memory cells can be compared with a predetermined range of a fraction of memory cells in the respective page to evaluate the plurality of read voltages (e.g., whether any of the read voltages is in a wrong voltage range).

In some aspects of the present disclosure, a memory device is disclosed. In some aspects, the memory device includes a plurality of memory cells arranged in an array, an input/output (I/O) interface connected to the plurality of memory cells to output data signal from each memory cell, and a control circuit. In some embodiments, the control circuit includes a first clock generator to generate a first clock signal and a second clock signal according to an input clock signal and a chip enable (CE) signal and provide the first clock signal to the plurality of memory cells. In some embodiments, the control circuit includes a second clock generator to generate a third clock signal according to the input clock signal and a DFT (design for testability) enable signal. In some embodiments, the control circuit generates an output clock signal according to the second clock signal or the third clock signal.

In some aspects of the present disclosure, a memory device is disclosed. In some aspects, the memory device includes a plurality of memory cells arranged in an array, an input/output (I/O) interface connected to the plurality of memory cells to output data signal from each memory cell, and a control circuit. In some embodiments, the control circuit includes a first clock generator to generate a first clock signal and a second clock signal according to an input clock signal and a chip enable (CE) signal and provide the first clock signal to the plurality of memory cells. In some embodiments, the control circuit includes a second clock generator to generate a third clock signal according to the input clock signal and a DFT (design for testability) enable signal. In some embodiments, the control circuit generates an output clock signal according to the second clock signal or the third clock signal.

An example system comprises: a master bus electrically coupled to a master multiplexer controlled by a test mode signal selecting between a master physical interface (PHY) and a slave bus of a plurality of slave buses, wherein each slave bus is electrically coupled to a respective slave multiplexer selecting between a respective slave PHY and the master bus; a plurality of electrical circuits, wherein each electrical circuit of the plurality of electrical circuits is electrically coupled to one of: the master bus or a slave bus of the plurality of slave buses; and a memory test interface electrically coupled to the master bus.

An apparatus includes a first group of memory units and a second group of memory units coupled to a first data path and a second data path coupled to a controller, a first delay element on the first data path coupled to the second group of memory units and configured to send, from the controller to the second group of memory units, signals for write and read operations in a sequence of time cycles delayed by a time cycle with respect to the first group of memory units, and a second delay element on the second data path and coupled to the first group of memory units and configured to send, from the first group of memory units to the controller, test result signals delayed by a time cycle, the delayed test result signals having a matching delay to the delayed write and read operations.