Abstract: A memory interface may include a transmitter that generates multi-level signals made up of symbols that convey multiple bits of data. The transmitter may include a first data path for a first bit (e.g., a least significant bit (LSB)) in a symbol and a second data path for a second bit (e.g., the most significant bit (MSB)) in the symbol. Each path may include a de-emphasis or pre-emphasis buffer circuit that inverts and delays signals received at the de-emphasis or pre-emphasis buffer circuit. The delayed and inverted data signals may control de-emphasis or pre-emphasis drivers that are configured to apply de-emphasis or pre-emphasis to a multi-level signal.

Abstract: Methods, systems, and devices for crosstalk cancellation for signal lines are described. In some examples, a device (e.g., a host device or a memory device) may generate a first signal and may invert the first signal to obtain an inverted first signal. The device may obtain a second signal based on attenuating a first range of frequencies of the inverted first signal and a second range of frequencies of the inverted first signal, where the first range of frequencies is below a first threshold frequency and the second range of frequencies is above a second threshold frequency that is greater than the first threshold frequency. The device may transmit the first signal via a first signal line of a set of signal lines and the second signal line via a second signal line of the set of signal lines.

Abstract: Methods, systems, and devices for channel modulation for a memory device are described. A system may include a memory device and a host device coupled with the memory device. The system may be configured to communicate a first signal modulated using a first modulation scheme and communicate a second signal that is based on the first signal and that is modulated using a second modulation scheme. The first modulation scheme may include a first quantity of voltage levels that span a first range of voltages, and the second modulation scheme may include a second quantity of voltage levels that span a second range of voltages different than (e.g., smaller than) the first range of voltages. The first signal may include write data carried over a data channel, and the second signal may include error detection information based on the write data that is carried over an error detection channel.

Abstract: An apparatus is provided, comprising a plurality of memory devices and a buffering device that permits memory devices with a variety of physical dimensions and memory formats to be used in an industry-standard memory module format. The buffering device includes memory interface circuitry and at least one first-in first-out (FIFO) or multiplexer circuit. The apparatus further comprises a parallel bus connecting the buffering device to the plurality of memory devices. The parallel bus includes a plurality of independent control lines, each coupling the memory interface circuitry to a corresponding subset of a plurality of first subsets of the plurality of memory devices. The parallel bus further includes a plurality of independent data channels, each coupling the at least one FIFO circuit or multiplexer circuit to a corresponding subset of a plurality of second subsets of the plurality of memory devices.

Abstract: Systems and methods for implementation of modified decision feedback equalization. In one embodiment, a method, includes sweeping a reference voltage signal across a set of voltages to find a center point of an eye diagram, determining whether an asymmetry is present in the eye diagram relative to the center point of the eye diagram, and when an asymmetry is determined to be present, generating a control signal to select a mode of decision feedback equalization to be applied to an input data bit.

Abstract: A memory subsystem architecture that includes clock signal routing architecture to split a clock signal to support two register clock driver (RCD) devices. The clock signal routing architecture may include clock signal splitter circuit that enables contemporaneous provision of a common clock signal to the two register clock driver devices. The clock signal splitter circuit may have three legs: a first leg to receive the clock signal from an external bus, and two similar legs to route the clock signal to the RCD devices.

Abstract: Apparatuses, systems, and methods for high-pass filtering pre-emphasis circuits. A device may use a pre-emphasis driver to provide a multi-level signal based on multiple binary signals. The pre-emphasis driver includes a primary driver coupled in parallel with at least one equalizer path, each of which includes an equalizer driver and a filtering element. The filtering element may be an AC filtering element, such as a capacitor. The equalizer paths may contribute equalized signal(s) which have a high-pass filtering behavior. The pre-emphasis circuit may combine the primary signal from the primary driver and the equalized signals to generate an overall output multi-level signal. In some embodiments, the pre-emphasis driver may be a pulse amplitude modulated (PAM) driver, such as a PAM4 driver with four levels of the multi-level driver.

Abstract: Methods, systems, and devices for techniques for time-variable decision feedback equalization are described. A memory device may be coupled with a host device using one or more conductive lines. A receiver may receive a signal transmitted from another device over a conductive line. The receiver may include a decision circuit used to determine voltages of the received signal based on the received signal and a feedback signal and output an output signal. The receiver may include a variable time-delay circuit configured to output delayed signals that are delayed versions of the output signal and a gain circuit that is configured to scale the delayed signals to generate the feedback signal. The variable time-delay circuit may include delay elements having variable delay parameters. The receiver may be coupled with a memory array that stores the information conveyed by the output signal.

Abstract: An apparatus is provided, comprising a plurality of memory devices and a buffering device that permits memory devices with a variety of physical dimensions and memory formats to be used in an industry-standard memory module format. The buffering device includes memory interface circuitry and at least one first-in first-out (FIFO) or multiplexer circuit. The apparatus further comprises a parallel bus connecting the buffering device to the plurality of memory devices. The parallel bus includes a plurality of independent control lines, each coupling the memory interface circuitry to a corresponding subset of a plurality of first subsets of the plurality of memory devices. The parallel bus further includes a plurality of independent data channels, each coupling the at least one FIFO circuit or multiplexer circuit to a corresponding subset of a plurality of second subsets of the plurality of memory devices.

Abstract: Methods, systems, and devices for channel modulation for a memory device are described. A system may include a memory device and a host device coupled with the memory device. The system may be configured to communicate a first signal modulated using a first modulation scheme and communicate a second signal that is based on the first signal and that is modulated using a second modulation scheme. The first modulation scheme may include a first quantity of voltage levels that span a first range of voltages, and the second modulation scheme may include a second quantity of voltage levels that span a second range of voltages different than (e.g., smaller than) the first range of voltages. The first signal may include write data carried over a data channel, and the second signal may include error detection information based on the write data that is carried over an error detection channel.

Abstract: Methods, systems, and devices for communicating data with stacked memory dies are described. A first semiconductor die may communicate with an external computing device using a binary-symbol signal including two signal levels representing one bit of data. Semiconductor dies may be stacked on one another and include internal interconnects (e.g., through-silicon vias) to relay an internal signal generated based on the binary-symbol signal. The internal signal may be a multi-symbol signal modulated using a modulation scheme that includes three or more levels to represent more than one bit of data. The multi-level symbol signal may simplify the internal interconnects. A second semiconductor die may be configured to receive and re-transmit the multi-level symbol signal to semiconductor dies positioned above the second semiconductor die.

Abstract: Methods, systems, and devices that support variable modulation schemes for memory are described. A device may switch between different modulation schemes for communication based on one or more operating parameters associated with the device or a component of the device. The modulation schemes may involve amplitude modulation in which different levels of a signal represent different data values. For instance, the device may use a first modulation scheme that represents data using two levels and a second modulation scheme that represents data using four levels. In one example, the device may switch from the first modulation scheme to the second modulation scheme when bandwidth demand is high, and the device may switch from the second modulation scheme to the first modulation scheme when power conservation is in demand. The device may also, based on the operating parameter, change the frequency of the signal pulses communicated using the modulation schemes.

Abstract: Methods, systems, and devices for techniques for time-variable decision feedback equalization are described. A memory device may be coupled with a host device using one or more conductive lines. A receiver may receive a signal transmitted from another device over a conductive line. The receiver may include a decision circuit used to determine voltages of the received signal based on the received signal and a feedback signal and output an output signal. The receiver may include a variable time-delay circuit configured to output delayed signals that are delayed versions of the output signal and a gain circuit that is configured to scale the delayed signals to generate the feedback signal. The variable time-delay circuit may include delay elements having variable delay parameters. The receiver may be coupled with a memory array that stores the information conveyed by the output signal.

Abstract: Methods, systems, and devices for multiplexing distinct signals on a single pin of a memory device are described. Techniques are described herein to multiplex data using a modulation scheme having at least three levels. The modulated data may be communicated to multiple memory dies over a shared bus. Each of the dies may include a same or different type of memory cell and, in some examples, a multi-level signaling scheme may be pulse amplitude modulation (PAM). Each unique symbol of the modulated signal may be configured to represent a plurality of bits of data.

Abstract: Described apparatuses and methods are directed to equalization with pulse-amplitude modulation (PAM) signaling. As bus frequencies have increased, the time for correctly transitioning between voltage levels has decreased, which can lead to errors. Symbol decoding reliability can be improved with equalization, like with decision-feedback equalization (DFE). DFE, however, can be expensive for chip area and power usage. Therefore, instead of applying DFE to all voltage level determination paths in a receiver, DFE can be applied to a subset of such determination paths. With PAM4 signaling, for example, a DFE circuit can be coupled between an output and an input of a middle slicer. In some cases, symbol detection reliability can be maintained even with fewer DFE circuits by compressing a middle eye of the PAM4 signal. The other two eyes thus have additional headroom for expansion. Encoding schemes, impedance terminations, or reference voltage levels can be tailored accordingly.

Abstract: Described apparatuses and methods enable communication between a host device and a memory device to establish relative delays between different data lines. If data signals propagate along a bus with the same timing, simultaneous switching output (SSO) and crosstalk can adversely impact channel timing budget parameters. An example system includes an interconnect having multiple data lines that couple the host device to the memory device. In example operations, the host device can transmit to the memory device a command indicative of a phase offset between two or more data lines of the multiple data lines. The memory device can implement the command by transmitting or receiving signals via the interconnect with different relative phase offsets between data lines. The host device (e.g., a memory controller) can determine appropriate offsets for a given apparatus. Lengths of the offsets can vary. Further, a system can activate the phase offsets based on frequency.

Abstract: Techniques are provided herein to increase a rate of data transfer across a large number of channels in a memory device using multi-level signaling. Such multi-level signaling may be configured to increase a data transfer rate without increasing the frequency of data transfer and/or a transmit power of the communicated data. An example of multi-level signaling scheme may be pulse amplitude modulation (PAM). Each unique symbol of the multi-level signal may be configured to represent a plurality of bits of data.

Abstract: Apparatuses, such as semiconductor device packages, may include, for example, a device substrate including a semiconductor material and bond pads coupled with an active surface of the device substrate. A package substrate may be secured to the device substrate, the package substrate configured to route signals to and from the bond pads. A ball grid array may be supported on, and electrically connected to, the package substrate. Each ball of the ball grid array positioned and configured to carry a clock signal or a strobe signal may be located in a central column of the ball grid array.

Abstract: Apparatuses, systems, and methods for high-pass filtering pre-emphasis circuits. A device may use a pre-emphasis driver to provide a multi-level signal based on multiple binary signals. The pre-emphasis driver includes a primary driver coupled in parallel with at least one equalizer path, each of which includes an equalizer driver and a filtering element. The filtering element may be an AC filtering element, such as a capacitor. The equalizer paths may contribute equalized signal(s) which have a high-pass filtering behavior. The pre-emphasis circuit may combine the primary signal from the primary driver and the equalized signals to generate an overall output multi-level signal. In some embodiments, the pre-emphasis driver may be a pulse amplitude modulated (PAM) driver, such as a PAM4 driver with four levels of the multi-level driver.

Abstract: Techniques are provided herein to increase a rate of data transfer across a large number of channels in a memory device using multi-level signaling. Such multi-level signaling may be configured to increase a data transfer rate without increasing the frequency of data transfer and/or a transmit power of the communicated data. An example of multi-level signaling scheme may be pulse amplitude modulation (PAM). Each unique symbol of the multi-level signal may be configured to represent a plurality of bits of data.