2 SEE Mechanisms

The primary single-event effect (SEE) events of interest in the OPA4H199-SEP is the destructive single-event latch-up (SEL). From a risk/impact point-of-view, the occurrence of an SEL is potentially the most destructive SEE event and the biggest concern for space applications. The LBC9 process node was used for the OPA4H199-SEP. CMOS circuitry introduces a potential for SEL susceptibility. SEL can occur if excess current injection caused by the passage of an energetic ion is high enough to trigger the formation of a parasitic cross-coupled PNP and NPN bipolar structure (formed between the p-sub and n-well and n+ and p+ contacts). The parasitic bipolar structure initiated by a single-event creates a high-conductance path (inducing a steady-state current that is typically orders-of-magnitude higher than the normal operating current) between power and ground that persists (is “latched”) until power is removed or until the device is destroyed by the high-current state. The process modifications applied for SEL-mitigation were sufficient as the OPA4H199-SEP exhibited no SEL with heavy-ions up to an LET_EFF of 43 MeV-cm²/mg at a fluence of 10⁷ ions/cm² and a chip temperature of 125°C.

The OPA4H199-SEP was biased in a buffer configuration where V+ is set to 20 V and V- is set to -20 V. On all 4 channels, the inverting input was connected to the output. Current was monitored over time for both V+ and V-. Heavy ions with LET_EFF = 43 MeV-cm²/mg were used to irradiate the devices. Flux of 10⁵ ions/s-cm² and fluence of 10⁷ ions/cm² were used during the exposure at 125°C temperature.