Analog and mixed-signal test has been running without an objective coverage metric since the discipline existed. Digital test teams can measure what fraction of faults a test set exercises. AMS teams could not: behavior does not compress cleanly into a single expected result, process variation is indistinguishable from soft failures, and the coupling between device behavior and test path variation is hard to separate. The result was conservative overtest: run everything, spend the full budget, accept the cost. IEEE 2427-2025, ratified in January 2026, establishes the first standard framework for quantifying defect coverage in AMS circuits.
The standard matters because it is a prerequisite, not a solution. Before 2427-2025, adaptive test flows for AMS chips had no objective gate. Teams could not confidently reduce test depth without a coverage metric to show they were not dropping fault capture. The new standard creates the measurement layer that makes optimization arguable. IC makers that adopt it gain something they have never had: a number to defend when they propose cutting test time.
The remaining obstacle is separating device variation from test-path variation, which is harder in analog than in digital. Every measurement in AMS test reflects both the device under test and the measurement instrument. 2427-2025 sets the coverage framework but leaves the calibration methodology to implementers. That gap is where the next round of ATE software will differentiate.
Teradyne and Advantest now have a standard to implement against. Teams that retrofit existing flows with 2427-2025 coverage metrics in the next 12 months will be able to negotiate test time reductions with their customers before vendor tooling commoditizes the standard. The window to use it as a competitive lever is roughly 18-24 months.