A built-in current sensor based on current-mode design

A very simple yet powerful design of a built-in current sensor for CMOS I/sub DDQ/ testing is presented. Compared with previous methods, this design has lower sensitivity to parameter deviation caused by process or temperature variations. In addition, this design provides scalable sensing resolutions and programmable current reference. Experimental results show that a test response time of less than 2 ns can be acquired when the faulty I/sub DDQ/ current is higher than 250 /spl mu/A.