Catastrophic latchup in a CMOS operational amplifier

We report catastrophic single-event latchup results for a CMOS operational amplifier. Thermal and optical imagings in conjunction with current distributions were used to identify latchup-sensitive regions. Differences in cross section for various ions show that charge is collected at depths beyond 40 μm, causing the cross section to be underestimated unless long-range ions are used. Latchup testing with short-range ions may underestimate the cross section or even fail to trigger a latchup event that would occur with more energetic ions.