Ampere Computing LLC

Yeshwant Kolla

Babji Vallabhaneni

Ashish Akhilesh

Rahul Nadkarni

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

Methods and systems for on-die measuring jitter of a clock under test are presented. In an aspect, an apparatus comprises a delay line having a plurality of delay elements, the outputs of which are sampled at the expected transition time of the clock under test. The sampled outputs are provided to an edge detector that indicates the presence of the clock transition at a specific time, and a latching circuit stores a record of all the edge locations seen during a sampling window. In some aspects, a counting circuit counts and stores how many times the transition occurs at each specific time during the sampling window. The counts stored by the counting circuit provide histogram data that can be analyzed to determine the jitter characteristics of the clock under test.

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Wake Forest, NC, United States of America

Yeshwant Kolla