Apparatuses and methods for calculating row hammer refresh addresses in a semiconductor device

1. An apparatus comprising:

a refresh address control circuit comprising:

a shift register configured to store a plurality of previously-sampled row addresses corresponding to respective rows of memory cells and to receive a new sample row address corresponding to a first row of memory cells, wherein, in response to a sampling signal, the shift register is configured to provide an indication of a row hammer attack in response to detection of a match between the new sample row address and one of the plurality of previously-sampled row addresses; and

an address scrambler circuit configured to receive the indication of the row hammer attack and the new sample row address, wherein the address scrambler circuit is further configured to perform first and second sets of logical operations on a first subset of bits of the new sample row address to provide a first subset of bits of a victim row address corresponding to a second row of memory cells physically adjacent to the first row of memory cells, wherein the address scrambler circuit is configured to perform bitwise exclusive OR operations as part of the first or second sets of logical operations.

2. The apparatus of claim 1 , wherein the address scrambler circuit is further configured to perform the first and second sets of logical operations on the first subset of bits of the new sample row address to provide a second subset of bits of a second victim row address corresponding to a third row of memory cells physically adjacent to the first row of memory cells.

3. The apparatus of claim 1 , wherein the address scrambler circuit is configured to perform the first set of logical operations by performing bitwise comparisons between a set of three bits of the first subset of bits and bitwise comparisons between a set of two bits of the first subset of bits.

4. The apparatus of claim 3 , wherein the set of three bits of the first subset of bits partially overlaps with the set of two bits of the first subset of bits.

5. The apparatus of claim 1 , wherein the address scrambler circuit is further configured to determine a second subset of bits of the victim row address based on a second subset of bits of the new sample row address.

6. The apparatus of claim 5 , wherein the address scrambler circuit is further configured to determine a carry bit based on the first subset of bits of the new sample row address and is configured to determine the second subset of bits of the victim row address further based on the carry bit.

7. The apparatus of claim 5 , wherein the address scrambler circuit is further configured to determine a polarity bit based on a first bit of the first subset of bits of the new sample row address and is configured to determine the second subset of bits of the victim row address further based on the polarity bit.

8. The apparatus of claim 1 , wherein the shift register comprises a plurality of sets of flip-flops each configured to store respective one of the plurality of previously-sampled row addresses.

9. The apparatus of claim 8 , wherein a first set of flip-flops of the plurality of sets of flip-flops is configured to store an output of a second set of flip-flops of the plurality of sets of flip-flops in response to the sampling signal.

10. A method comprising:

in response to a sampling signal, providing an indication of a row hammer attack in response to detection of a match between the new sample row address and one of a plurality of previously-sampled row addresses; and

in response to the indication of the row hammer attack:

performing first and second sets of logical operations on a first subset of bits of the new sample row address to provide a subset of bits of a victim row address corresponding to a second row of memory cells physically adjacent to the first row of memory cells; and

determining a second subset of bits of the victim row address based on a second subset of bits of the new sample row address.

11. The method of claim 10 , further comprising performing the first and second sets of logical operations on the first subset of bits of the new sample row address to provide a second subset of bits of a second victim row address corresponding to a third row of memory cells physically adjacent to the first row of memory cells.

12. The method of claim 10 , further comprising performing bitwise exclusive OR operations as part of the first or second sets of logical operations.

13. The method of claim 10 , further comprising performing the first set of logical operations performed by performing bitwise comparisons between a set of three bits of the first subset of bits and bitwise comparisons between a set of two bits of the first subset of bits.

14. The method of claim 13 , wherein the set of three bits of the first subset of bits partially overlaps with the set of two bits of the first subset of bits.

15. The method of claim 10 , further comprising:

determining a carry bit based on the subset of bits of the new sample row address; and

determining the second subset of bits of the victim row address further based on the carry bit.

16. The method of claim 10 , further comprising:

determining a polarity bit based on a first bit of the subset of bits of the new sample row address; and

determining the second subset of bits of the victim row address further based on the polarity bit.

17. The method of claim 10 , further comprising storing each of the plurality of previously-sampled row addresses via respective set of a plurality of sets of flip-flops.

18. The method of claim 10 , wherein the first and second logical operations include common logical operations.