Patent ID: 7646203

Claim:
A method for performing an open test for analyzing an open in a test route of an integrated circuit comprising: connecting a pull-down device between an input terminal of an analog-to-digital converter and ground; connecting an open calibration test route between a test input terminal and the input terminal of the analog-to-digital converter; applying an input voltage to the test input terminal; applying a reference voltage to a reference input terminal of the analog-to-digital converter; adjusting the reference voltage until an output code of the analog-to-digital converter is equal to a predetermined code and setting the adjusted reference voltage as a preset reference voltage; connecting the test route between the test input terminal and the input terminal of the analog-to-digital converter; applying the input voltage to the test input terminal; applying the preset reference voltage to the reference input terminal of the analog-to-digital converter; and determining whether the test route is open by comparing an output code of the analog-to-digital converter with the predetermined code.