Demonstrated in this paper is a technique for automatic circuit resizing between different technologies. It is not based on any optimization techniques, but rather relies on a new algorithm based on knowledge extraction, which makes it a very fast technique. This technique studies the original design and extracts its major features (basic devices & blocks features, device matching, parasitics, symmetry) and then produces a re-sized design in the target technology with the same performance as the original design. The migration of a low voltage Delta Sigma modulator is presented in this paper to validate the migration engine.