What is spec-driven design? In the digital world, the answer is simple: digital synthesis. In the analog
world, however, it can mean anything along the automation scale from simply having the
specs defined before the design work begins to analog synthesis and anything in between.
Typically, the systems architect or design project leader creates the specs (measurements along with
minimum/maximum values) that the overall design must achieve. The designer may create specs for the
blocks for which s/he is responsible, or the systems architect may create the block-level specs as well. For
example, if a designer is given the task of designing a voltage-controlled oscillator (VCO), s/he may be
told that the frequency gain must be between 1 MHz/V and 2 MHz/V, and that the high voltage must be
between 4.5 V and 5.5 V. The designer must create a VCO that meets those specs. How much of the work
is manual and how much can be driven from the spec has a direct effect on how productive the designer
can be and how quickly s/he can turn the design around.
