First signaling indicative of instructions to enter a self-refresh (SREF) mode can be received concurrently by a plurality of memory dies. Responsive to a memory die of the plurality of memory dies entering the SREF mode, self-refreshing of memory banks of the memory die can be delayed, at the memory die and based on fuse states of an array of fuses of the memory die, an amount of time relative to receipt of the signaling by the memory die. Delaying self-refreshing of memory banks of memory dies in a staggered, or asynchronous, manner can evenly distribute power consumption of the memory dies so that the likelihood of an associated power spike is reduced or eliminated.

Several embodiments of memory devices and systems with selective page-based refresh are disclosed herein. In one embodiment, a memory device includes a controller operably coupled to a main memory having at least one memory region comprising a plurality of memory pages. The controller is configured to track, in one or more refresh schedule tables stored on the memory device and/or on a host device, a subset of memory pages in the plurality of memory pages configured to be refreshed according to a refresh schedule. In some embodiments, the controller is further configured to refresh the subset of memory pages in accordance with the refresh schedule.

A memory may include multiple rows each coupled to multiple memory cells; a target row classification circuit suitable for classifying, as a target row, a row, among the multiple rows, that is susceptible to data loss as a result of activity of an adjacent row; and a target row signal generation circuit suitable for sequentially activating a target row active signal for activating the target row and a target row precharge signal for precharging the target row in response to a precharge command.

A semiconductor memory device and a memory system are provided. The semiconductor memory device includes a memory cell array, a normal refresh row address generator, a hammer refresh row address generator, a refresh selection signal generator, and a selector. The normal and hammer refresh row address generators generates a normal refresh row address and a hammer refresh row address, respectively, in response to a refresh counting control signal. The refresh selection signal generator sequentially generates normal and hammer refresh selection signals in response to the refresh counting control signal. The selector selects the normal refresh row address or the hammer refresh row address in response to the normal and hammer refresh selection signals. A normal refresh operation and a hammer refresh operation are sequentially performed on a memory cell array block among plural memory cell array blocks in response to the refresh row address.

A semiconductor memory device includes a memory cell array including a plurality of memory cell rows, a row hammer management circuit, and a refresh control circuit. The row hammer management circuit captures row addresses accompanied by first active commands randomly selected from active commands, each of which has a first selection probability that is uniform, from an external memory controller during a reference time interval, and selects at least one row address from among the captured row addresses as a hammer address a number of times proportional to access counts of an active command corresponding to the at least one row address during the reference time interval. The refresh control circuit receives the hammer address and performs a hammer refresh operation on one or more victim memory cell rows which are physically adjacent to a memory cell row corresponding to the hammer address.

An operating method of a memory device, the method including, receiving a row address, determining whether an operating mode is a byte mode, counting up an access count value for the row address while ignoring a page bit, when the operating mode is the byte mode, selecting a target row hammer address among target row addresses using access count values for the target row hammer address, calculating a victim row address corresponding to the target row hammer address, and performing a target refresh operation on the victim row address.

A memory device includes a memory cell array including a plurality of memory cells connected to a plurality of wordlines and a plurality of bitlines, a target row refresh logic circuit configured to select a target row address from among a plurality of target row addresses as a refresh row address based on victim point values, and perform a refresh operation on first memory cells of the plurality of memory cells connected to a wordline of the plurality of wordlines indicated by the refresh row address, a victim point table configured to store the victim point values for the target row addresses, and a victim point accumulator configured to receive a first row address from an external device, and accumulate a first victim point value for at least one target row address corresponding to the first row address during a unit time period.

A memory device may enforce compliance with a refresh command requirement in some examples. When a controller fails to comply with the refresh command requirement, the memory device may prevent the controller from accessing a memory array. The controller may regain access by providing one or more commands, such as a refresh command. In some examples, the memory may enforce compliance with a refresh command requirement responsive to a value written to the mode register. In some examples, the memory may enforce compliance with the refresh command requirement after an initialization operation has completed.

Disclosed herein is an apparatus that includes a plurality of memory banks and a refresh controller configured to perform a refresh operation on one or more of the plurality of memory banks having a first state without performing the refresh operation on one or more of the plurality of memory banks having a second state responsive to a first refresh command, and perform the refresh operation on a selected one of the plurality of memory banks responsive to a second refresh command. The refresh controller is configured to bring the selected one of the plurality of memory banks into the second state when the refresh operation is performed responsive to the second refresh command.

A memory system includes: a plurality of memory chips each including a plurality of banks and each suitable for generating a tracking address by tracking a row-hammer risk of selected banks among the banks, encrypting the tracking address using an encryption key to output tracking information to a corresponding data bus of a plurality of data buses and performing a target refresh operation according to a row-hammer address transferred through a command/address bus; and a memory controller suitable for collecting the tracking information for the banks transferred through the plurality of data buses to generate and output the row-hammer address to the command/address bus.