  This paper introduces new perspectives on analog design space search. To
minimize the time-to-market, this endeavor better cast as constraint
satisfaction problem than global optimization defined in prior arts. We
incorporate model-based agents, contrasted with model-free learning, to
implement a trust-region strategy. As such, simple feed-forward networks can be
trained with supervised learning, where the convergence is relatively trivial.
Experiment results demonstrate orders of magnitude improvement on search
iterations. Additionally, the unprecedented consideration of PVT conditions are
accommodated. On circuits with TSMC 5/6nm process, our method achieve
performance surpassing human designers. Furthermore, this framework is in
production in industrial settings.
