Application of a Pulsed Laser to Identify a Single-Event Latchup Precursor

Focused, pulsed laser-light is used to investigate single-event latchup in an analog-to-digital converter (AD9240) through the generation of charge collection spectra and their dependence on bias, laser pulse intensity and strike location. Large bipolar single-event transients were identified as precursors to latchup. They occurred at bias voltages just below the latchup holding voltage and in regions that became sensitive to single-event latchup at voltages above the holding voltage. Charge collection spectra obtained from spatial scans involving the pulsed laser had features similar to those obtained from heavy-ion irradiation. Both approaches indicated enhanced charge collection at supply voltages just below the holding voltage.