IDDQ4

IDDQ4 is a term that emerged in the context of studying and diagnosing certain types of semiconductor defects. Specifically, it relates to the quiescent power supply current (IDDQ) measurement as a testing methodology for integrated circuits. IDDQ testing involves measuring the current flowing from the power supply to ground when the circuit is in a static, or quiescent, state. Normally, this current should be very low. A significant increase in IDDQ is indicative of a defect within the chip, such as a stuck-at fault or a bridging fault.

The designation "IDDQ4" typically refers to a specific scenario or state encountered during IDDQ testing, though its precise meaning can vary depending on the specific testing framework or the context of the research or development being discussed. It's not a universally defined standard like a particular IEEE protocol. In some contexts, it might represent a threshold value, a particular pattern of test vectors that triggers a specific type of fault, or a category of defect identified by a certain IDDQ level. Without more specific information about the origin of the term, it's difficult to provide a definitive, singular explanation. However, its presence suggests a systematic approach to defect analysis using IDDQ measurements. The goal of such categorizations is to more efficiently pinpoint and understand the nature of manufacturing defects in integrated circuits.