Vectorless Approach of Device under Test Testing
A method and associated system for testing a plurality of devices under test with internal sources of stimuli. The method feeds back outputs of the plurality of devices under test as inputs to the plurality of devices under tests, wherein the fed-back output is an internal source of the stimuli and represents informational entropy of each device under test. The method provides drive signals to each of the plurality of devices under test. The method collects results output from each of the plurality of devices under test provided with the drive signals and compares the results between the plurality of devices under test. The method identifies the devices passing the test as the devices where the results show homogenous behavior.
1 . A method for testing a plurality of devices under test with internal sources of stimuli, the method comprising:
feeding back outputs of the plurality of devices under test as inputs to the plurality of devices under tests, wherein each of the fed-back output is an internal source of the stimuli and represents informational entropy of each device under test;
providing drive signals to each of the plurality of devices under test;
collecting results output from each of the plurality of devices under test provided with the drive signals and comparing the results between the plurality of devices under test; and
identifying the devices passing the test as the devices where the results show homogenous behavior.
2 . The method of claim 1 , wherein the feeding back outputs comprises utilizing a switchboard to connect data flow between an output of each of the plurality of devices under test back to an input of each of the plurality of devices under test.
3 . The method of claim 2 , wherein the switchboard provides dynamic commutation of the feed-back to increase randomness of the feed-back.
4 . The method of claim 2 , wherein the providing drive signals comprises utilizing a controller providing a continuous signal to drive the plurality of devices under test.
5 . The method of claim 4 , wherein the collecting results output from each of the plurality of devices under test comprises utilizing a register to collect the results over time of testing of the plurality of devices under test.
6 . The method of claim 1 , wherein the collecting results output from each of the plurality of devices under test comprises collecting the results from a population of devices being manufactured.
7 . The method of claim 6 , wherein the collecting the results from the population comprises collecting the results from a whole of the population.
8 . The method of claim 6 , wherein the collecting the results from the population comprises collecting the results from a fraction of the population.
9 . The method of claim 7 , wherein the fraction of the population from which the results are collected is determined based at least on a total number of devices in the population and an expected manufacturing yield.
10 . The method of claim 1 , wherein the identifying the devices passing the test does not utilize expected output values for the devices under test derived from an outside source.
11 . A system for testing a plurality of devices under test with internal sources of stimuli, the system comprising:
the plurality of devices under test, wherein each of the plurality of devices under test comprises
a switchboard configured to connect data flow between an output of each of the plurality of devices under test back to an input of each of the plurality of devices under test;
a controller configured to provide a drive signal to each of the plurality of devices under test;
a register configured to collect the results over time of testing of the plurality of devices under test provided with respective drive signals; and
a comparator configured to compare the results between the plurality of devices under test,
wherein the data flow between the output of each of the plurality of devices under test back to the input of each of the plurality of devices under test provides an internal source of the stimuli and represents informational entropy of each device under test.
12 . The system of claim 11 , wherein the comparator is configured to collect results output from each of the plurality of devices under test and compare the results between the plurality of devices under test.
13 . The system of claim 11 , wherein the comparator is configured to identify the devices passing the test as the devices where the results show homogenous behavior.
14 . The system of claim 11 , wherein the switchboard is configured to provide dynamic commutation of the feed-back to increase randomness of the feed-back.
15 . The system of claim 11 , wherein the controller is configured to provide a continuous signal to drive the plurality of devices under test.
16 . The system of claim 11 , wherein the comparator is configured to collect the results from a population of devices being manufactured
17 . The system of claim 16 , wherein the comparator is configured to collect the results from a whole of the population.
18 . The system of claim 11 , wherein the comparator is configured to collect the results from a fraction of the population.
19 . The system of claim 18 , wherein the fraction of the population from which the results are collected is determined based at least on a total number of devices in the population and an expected manufacturing yield.
20 . The system of claim 11 , wherein the comparator is configured to not to utilize expected output values for the devices under test derived from an outside source.