Patent ID: 9684025
Date: 2017-06-20
CPC Classifications: G01R,G05B,G06F

Claim:
1. A method for identifying open circuits using time domain reflectometry (TDR) comprising: providing a test setup comprising a tester coupled to a DUT board; placing all tester pins on said tester in a high impedance state; configuring a first tester I/O pin connected to a first DUT I/O pin as a tester output driving logic high; configuring said first tester I/O pin as a tester output logic low to introduce a negative edge signal; configuring said first tester I/O pin in a high impedance state; configuring said first tester I/O pin as tester input sampling a highest reliable sample rate generating a sample count; recording said sample count in a non-transitory computer storage readable medium; continually sampling said first tester I/O pin during prior two configuring and recording steps at highest reliable sample rate for enough time for reflection to propagate from said tester to said DUT and back to said tester; wherein said sampling step is based on detecting an increased voltage after time zero and generates sample values; storing said sample values into said non-transitory computer storage readable medium; repeating said configuring, sampling, and storing steps until all tester I/O pins connected to DUT I/O pins have been characterized and said sample values stored in said non-transitory computer storage readable medium; repeating said configuring, sampling, storing and prior repeating steps a desired number of times to determine a range of sample for each tester I/O and DUT I/O pin pair which represents an open circuit between said tester I/O and DUT I/O pin pair; inserting a DUT into said test setup; repeating said configuring, sampling and storing steps generating a recorded value for each tester I/O and DUT I/O pin pair; comparing said recorded value with said sample values to determine if the insertion of said DUT has changed a recorded pattern for each tester I/O and DUT I/O pin pair.