Summary: Single event latch-up (SEL) testing was performed on the Samsung K6R4008V1D and K6R4008C1D 3.3 and 5.0V 4M Asynchronous SRAMs (respectively) at the Texas A&M Cyclotron Institute. Single event latch-up (SEL) was tested at non-worst case room temperature conditions and worst-case voltage conditions (3.6 or 5.5V depending on part type). The Rev. D components were observed to be susceptible to SEL at a LET of 23.6 MeV·cm2/mg (3.6V and 25°C) and exhibited a very large latch-up error-cross section.