Take a look at slide 4. It occurred to me that the vendor / tool / language matrix was better suited to describing why we picked the approach we did. As such, I've removed the "substitution" column and moved it forward in the presentation. - It now explains why we picked Verilog-A as our initial implementation language (most tool support) - It also explains why we needed VHDL-AMS support (key vendor support) - Adding Sigrity and Apsim shows why we needed a substitution scheme and, by extension, adherence to basic SPICE element types Comments are welcome and appreciated. Todd. Todd Westerhoff High Speed Design Group Manager Cisco Systems 1414 Massachusetts Ave Boxboro, MA 01719 email:twesterh@xxxxxxxxx ph: 978-936-2149 ____________________________________________ "Always do right. This will gratify some people and astonish the rest." - Mark Twain