Transient-Induced Latchup in CMOS ICs Under Electrical Fast-Transient Test

The occurrence of transient-induced latchup (TLU) in CMOS integrated circuits (ICs) under electrical fast-transient (EFT) tests is studied. The test chip with the parasitic silicon-controlled-rectifier (SCR) structure fabricated by a 0.18-mum CMOS process was used in EFT tests. For physical mechanism characterization, the specific ldquoswept-backrdquo current caused by the minority carriers stored within the parasitic PNPN structure of CMOS ICs is the major cause of TLU under EFT tests. Different types of board-level noise filter networks are evaluated to find their effectiveness for improving the immunity of CMOS ICs against TLU under EFT tests. By choosing the proper components in each noise filter network, the TLU immunity of CMOS ICs against EFT tests can be greatly improved.