Hi, I was reading an article/report (http://www.designers-guide.org/Design/tdd-principles.pdf) about how Analogue and mixed-signal design methods are too bottom-up when they should be top-down (like the modern digital methods). Browsing around, I haven't found much material published on this topic since... What tools exist to fix it? I've found Spectre and HSSPICE as possibilities, but I don't know to what extent these address RTL verification and synthesis. Also, are there automated methods to verify "gate-level" analogue circuits? Thanks in advance!