Laser Voltage Tracing for Electrical Fault Isolation of Circuits Propagating Aperiodic Signals

Laser voltage imaging (LVI) and its derivatives are established techniques for isolating broken scan/JTAG chains which work on periodic signals, but are ineffective when debugging aperiodic signals. Laser voltage probing (LVP) works on one transistor at a time which makes it slow for certain debug. Laser voltage tracing (LVT), presented recently, has opportunity to perform an area investigation of aperiodic signals. This paper presents a few applications of this technique to fault isolation (FI).