Transient power supply voltage (V/sub DDT/) analysis for detecting IC defects

Transient power supply voltage (V/sub DDT/) analysis is a new testing technique demonstrated as a powerful alternative and complement to I/sub DDQ/ testing. V/sub DDT/ analysis takes advantage of the limited response time of a voltage supply to the changing power demand of an IC during operation. Changes in the V/sub DD/ response time can be used to detect increases in the power demand of a microcontroller with resolutions of 20 nA at 100 kHz, 1 /spl mu/A at 1 MHz, and 2.5 /spl mu/A at 1.5 MHz. These current sensitivities have been shown for ICs with very low I/sub DDQ/ (<100 nA) and for an IC with an intrinsic I/sub DDQ/>300 /spl mu/A. The present system uses 100 cycle averaging to compensate for low frequency "jitter". The V/sub DDT/ signal acquisition protocols, frequency versus sensitivity tradeoffs, hardware considerations, noise limitations, data examples, and areas for future research are described.