20-10-2012, 12:55 PM
ANALOG IC DESIGN
ANALOG IC.ppt (Size: 560.5 KB / Downloads: 40)
What is Analog IC Design?
Analog IC design is the successful implementation of analog circuits and systems using integrated circuit technology.
Circuits process signals continuous in time and continuous in amplitude
NEED
While many applications have replaced much analog circuitry with their digital counterparts, the need for analog circuit design is actually growing.
REASON-------
Consumer-focused electronics have become the driving force of industry,
But , consumer electronics has become all-digital, networked, sophisticated, and almost independent of time, place, physical embodiment, and content. Users expect their tailored audio and video content when, where, and how they want it, to their own schedule and convenience.
Analog in digital handset.
In a digital handset,
convert the voice signal to a digital stream (with an "analog" ADC).
But before conversion, need to filter it (using an analog filter).
What comes out to your ear must be converted from digital to analog.(DAC)
And there's an analog filter there to clean up that signal.
Getting the signal up onto the RF carrier,
power amplifier (PA),
analog circuitry is needed to control the PA to ramp it up and down, and to control the power,
Which Analog circuits?
If not for the multitude of analog and mixed-signal components that vendors have developed in the past decades, the digital media river would slow to a trickle. It takes countless A/D and D/A converters—audio, video, RF—to make it possible.
It also takes basic small-signal amplifiers, audio through RF power amplifiers,
disk-drive read/write circuitry,
motor controls, line drivers and receivers,
power-supply components,
touch-screen interfaces, display drivers,
thermal sensors and fan controls,
and much more, to make the digital world possible.
Approach
Develop a firm background on technology and modeling
Present analog integrated circuits in a hierarchical, bottom-up manner
Emphasize understanding and concept over analytical methods (simple models)
Illustrate the correct usage of the simulator in design
Develop design procedures that permit the novice to design complex analog circuits
(these procedures will be modified with experience)
Unique Features of Analog IC Design
Geometry is an important part of the design
Electrical Design →Physical Design →Test Design
Usually implemented in a mixed analog-digital circuit
Analog is 20% and digital 80% of the chip area
Analog requires 80% of the design time
Analog is designed at the circuit level
Passes for success: 2-3 for analog, 1 for digital
Skills Required for Analog IC Design
In general, analog circuits are more complex than digital
Requires an ability to grasp multiple concepts simultaneously
Must be able to make appropriate simplifications and assumptions
Requires a good grasp of both modeling and technology
Have a wide range of skills - breadth (analog only is rare)
Be able to learn from failure
Be able to use simulation correctly
Simulation “truths”:---(Usage of a simulator) x (Common sense) = Constant
Simulators are only as good as the models and the knowledge of those models by the designer
Simulators are only good if you already know the answers