Investigation and Mitigation of Analog SET on a Bandgap Reference in Triple-Well CMOS Using Pulsed Laser Techniques

The devices responsible for a 600-μs Analog Single-Event Transient (ASET) observed in an NPN Brokaw-cell type bandgap reference during heavy-ion irradiation are identified using pulsed laser techniques with two completely different experimental setups. The capability of focusing the beam to specific junctions provided by the lasers led to recognize a novel Long Duration Pulse (LDP) upset mechanism which, contrary to the conventional wisdom in the field, is promoted by heavy capacitive filtering applied to the circuit´s output. A thorough comprehension of the cause of the LDP allowed for the proposal of design measures of mitigation that were implemented in silicon. Final tests performed with the same laser setup confirmed the successful resolution of such analog SET problem in this popular class of circuits.