Ampere Computing LLC

Babji Vallabhaneni

Mitrajit Chatterjee

Rahul Nadkarni

Yeshwant Kolla

Vijay Parmar

Waseem Kraipak

David Hoff

Virtualized scan chain testing in a random access memory array, and related methods and computer-readable media are disclosed. To facilitate virtualized scan chain testing, the memory array includes an integrated test circuit that causes the memory array to behave as a serialized scan chain. The integrated test circuit forces serialized write and read access to offset entries in the memory array on each scan cycle in a scan mode based on received serialized test data. After the number of scan cycles equals the number of entries the memory array, the entries in the memory array are fully initialized with test data from the serial test data flow. In subsequent scan cycles, the integrated test circuit continues to perform serial read operations to cause stored serial test data to be serially shifted out as an output serial data flow that then be compared to the original serial test data.

Virtualized scan chain testing in a random access memory (RAM) array

An error injection system of a built-in self-repairable memory system renders the redundant spare columns of the repairable memory accessible to built-in self-test (BIST) read and write operations. To this end, the error injection system selectively injects fault data at one or more locations of the main memory during a BIST sequence, causing the BIST controller to issue a repair instruction that allocates one or more spare columns as replacement memory areas for the presumed faulty main memory locations. Thereafter, BIST read/write operations directed to the main memory locations will be performed on the allocated spare columns, thereby allowing the spare columns to be validated as part of the BIST. Injection of fault data to the main memory locations in this manner can also facilitate validation of the built-in self-repair logic by verifying the repair instruction codes that are generated in response to the injected faults.

Method to dynamically inject errors in a repairable memory on silicon and a method to validate built-in-self-repair logic

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Santa Clara, CA, United States of America

Babji Vallabhaneni