Apparatuses and methods for testing memory devices
Self-test circuits of memory devices disclosed herein may include circuitry that adjusts the correspondence between logical and physical addresses to match pre-repair mapping of memory locations. That is, if a memory device has been repaired by remapping logical addresses to new physical addresses, the circuitry of the test circuit restores the pre-repair mapping of the memory device in some examples. In some examples, an unused global column redundancy data path may be repurposed to provide repair information to the self-test circuit to implement the pre-repair mapping.
1 . An apparatus comprising:
a memory array including a plurality of column planes, wherein the plurality of column planes includes a global column redundancy plane; and
a test circuit comprising:
a comparator configured to compare internal read data from the memory array and expected read data, wherein the comparator is configured to provide error information based on comparing; and
a pre-repair map logic circuit configured to;
receive repair information and the error information and when the memory array has been repaired by remapping a logical address of a column plane of the plurality of column planes to a physical address of the global column redundancy plane, and
remap the logical address of the column plane of the plurality of column planes to a physical address of the column plane to restore a pre-repair mapping of the error information in the test circuit.
2 . The apparatus of claim 1 , wherein the test circuit further comprises an encoder configured to encode the error information provided by the pre-repair map logic circuit and provide encoded error information.
3 . The apparatus of claim 2 , wherein the test circuit further comprises a parallel serial converter configured to convert the encoded error information from parallel to serial data, wherein the parallel serial converter is further configured to provide serial encoded error information to at least one probe pad.
4 . The apparatus of claim 1 , wherein the pre-repair map logic circuit comprises a multiplexer, wherein a state of the multiplexer is based, at least in part, on the repair information.
5 . The apparatus of claim 1 , wherein the pre-repair map logic circuit comprises an address descrambler circuit.
6 . The apparatus of claim 1 , wherein the repair information is received from a data path of a global column redundancy circuit.
7 . An apparatus comprising:
a memory array comprising a plurality of column planes;
a global column redundancy circuit including a redundant column plane in the memory array;
a repair circuit configured to remap logical addresses of the plurality of column planes from original physical addresses to new physical addresses of the plurality of column planes and the redundant column plane when at least one of the plurality of column planes is a defective column plane; and
a test circuit including a pre-repair mapping circuit configured to receive data from at least a portion of the plurality of column planes and repair information from the global column redundancy circuit, wherein when the repair information indicates a repair has been performed on the defective column plane, the test circuit is configured to remap the logical addresses of the plurality of column planes to the original physical addresses of the plurality of column planes to restore a pre-repair mapping of the plurality of column planes within the test circuit.
8 . The apparatus of claim 7 , further comprising a data path coupled between the global column redundancy circuit and the test circuit, wherein the global column redundancy circuit is configured to provide the repair information to the test circuit via the data path.
9 . The apparatus of claim 7 , wherein the repair circuit comprises a first plurality of multiplexers and the test circuit comprises a second plurality of multiplexers.
10 . The apparatus of claim 7 , wherein the test circuit is configured to generate error information based, at least in part, on the pre-repair mapping and the data from at least the portion of the plurality of columns planes, and wherein the apparatus further comprises an external terminal configured to receive the error information.
11 . The apparatus of claim 10 , wherein the external terminal comprises a DQ pad.
12 . The apparatus of claim 10 , wherein the external terminal comprises a probe pad.
13 . A method comprising:
receiving repair information for a plurality of column planes of a memory array at a test circuit;
when the repair information indicates at least one of the plurality of column planes has been repaired using a redundant column plane of the memory array, restoring a pre-repair mapping of logical and physical addresses of the plurality of column planes by remapping the logical addresses to original ones of the plurality of column planes within the test circuit; and
when the repair information indicates no repair has been made, maintaining the pre-repair mapping of the logical and the physical addresses of the plurality of column planes within the test circuit.
14 . The method of claim 13 , wherein the repair information indicates a shift type repair, and restoring the pre-repair mapping comprises re-shifting a mapping of the plurality of column planes.
15 . The method of claim 13 , wherein the repair information indicates a direct type repair, and restoring the pre-repair mapping comprises descrambling an address of a mapping of the plurality of column planes.
16 . The method of claim 13 , wherein the repair information sets states of a plurality of multiplexers of the test circuit, and the states of the plurality of multiplexers restores the pre-repair mapping or maintains the pre-repair mapping.
17 . The method of claim 13 , wherein the repair information sets states of a plurality of address descrambler circuits of the test circuit, and the states of the plurality of address descrambler circuits restores the pre-repair mapping or maintains the pre-repair mapping.
18 . The method of claim 13 , further comprising repairing at least one of the plurality of column planes with a repair logic circuit of the test circuit, wherein the repair logic circuit is configured to perform a shift type repair or a direct type repair.
19 . The method of claim 13 , wherein the repair information is received by the test circuit via a data path coupled to a global column redundancy circuit.
20 . The method of claim 13 , further comprising:
receiving read data from the plurality of column planes at the test circuit;
receiving expected read data at the test circuit;
comparing the read data and the expected data;
generating error information based on the comparing;
encoding the error information; and
providing the error information to a probe pad.