In general there are two types of electronic circuits:

• Digital:circuits that process digitally encoded information or discrete signal levels directly such as to represent binary values of 0 and 1. These circuits use well defined building blocks which can be mass produced. Digital logic is its relatively easy to represent in software programs, therefore much of the digital design flow can be controlled or automated with software.
• Analog: all other types of circuits which process continuously varying signals. These circuits allow more flexibility in terms of achieving a desired result, hence the term custom design. Analog circuits are used in general when a digital system needs to address the real world to handle the physics, chemistry, biology, optics or fluidics – such as an antenna, microphone, loudspeaker, power supply, motor drive, sensors.

Modern systems use a combination of the two, this is terms analog-digital design or analog-mixed signal. Examples are signal convertors used in audio visual systems or software controlled radio used in a radar system.

Due to the immense variety of analog circuits, Analog Designers tend to specialize. In addition the use of tools to assist and automate quickly becomes pretty specialized, such as for high frequency signal design of radios.

The Analog designer is responsible to define, verify and validate analog circuits with the main deliverables being Circuit plans or specifications – to guide design or set targets Circuit schematics - showing symbolic layout of circuit function Circuit analytical models – to simulate behavior such as performance and consistency Circuit physical layouts – symbolic “floor plans” or actual geometric layout Circuit component and signal usage lists Additional circuit descriptions

Analog designers organize their work by way of modules, circuits, libraries and circuit elements. There are two main types of physical design that which is realized discrete components and analog semiconductor design; of course a combination is also used. The former tends to use pre-fabricated parts as “components”. The latter may be fabricated on a substrate, as a “chip”, with other semiconductor designs– analog or digital, alternatively their may be some substrate assembly prior to assembly with pre-fabricated components, such as on a printed circuit board.

The designer may have a role in defining specifications in collaboration with colleagues, System designers, Digital designers, other Analog designers. This is naturally a cross-discipline role as the analog designer will collaborate with those designing or “interfacing” with the real world.