Introduction

latchup overview is given at first, including the introduction of latchup phenomenon and characterization. The background of TLU is subsequently introduced, and the categories of several TLU-triggering modes are also summarized, including the power-on transition, transmission line reflections, supply voltage overshoots or undershoots, cable discharge event, and system-level ESD stresses. Furthermore, the recently-announced standard practice to evaluate the TLU immunity of CMOS ICs is also introduced. Compared with the conventional latchup standard commonly adopted in industry, this TLU standard practice has different test setup and latchup triggering source. It implies that the physical mechanism of TLU is different from the conventional latchup, and the foundation of TLU test standard is necessary.