What software is used by manufacturers to produce the thousands of data sheets for all of the products that they make? Specifically, the circuit diagrams which look very crisp, like they were made in a vector format. I assume that each manufacturer has some proprietary software that they use to produce these documents. Does anyone know what software can be used to produce professional looking diagrams with aesthetic and precise symbols? I've used plenty of CAD software such as Eagle and Orcad. These require you to choose a real world part before you can include it in your schematic. I'm looking for something more conceptual and quick, which I could use to quickly sketch out a diagram simply for visualization. For example, check out http://www.analog.com/static/imported-files/data_sheets/AD8231.pdf The figures are pleasing to my eye. Some parts and pins are labeled when necessary, but not when its unimportant, some optional components are shown with dotted lines, there are arrows indicating direction from output to input. I'm just wondering if there is software available to make diagrams that look very clean and clear and follow the conventions of circuit schematics.