What is latch-up?

Latch-up is a type of short circuit that can occur in CMOS integrated circuits. It involves the creation of a low-impedance path between the power supply rails (VCC and ground), leading to excessive current flow and potential device damage. It is caused by the parasitic bipolar transistors inherent in CMOS structures. Latch-up can be triggered by voltage transients, radiation, or input/output signals exceeding specified limits. Countermeasures include the use of guard rings, trench isolation, and careful circuit layout to minimize the gain of the parasitic transistors.