Course Learning Objectives
This course covers circuit and system level design issues of both analog and mixed-signal integrated circuits (IC).
Focusing mainly on CMOS and BiCMOS technologies, the key building blocks and issues for analog and mixed-signal ICs will be discussed in depth. Some topologies of DAC, ADC and non-standard mixed-signal circuits will be then discussed.
The main goal, more important than the mere knowledge of a number of circuit topologies, is to encourage the typical intuitive attitude required in the IC design (and in many areas of engineering) i.e. focusing the main design issues, individuating the trade-offs etc… This process must always precede the mathematical modeling of the circuit.
This course presumes a solid understanding of the basics of analog circuits.
1. Bipolar junction transistors (BJT)
Fundamentals of BJT physics and integrated BJT technologies, main difference with respect to CMOS.
Basic BJT stages. Bipolar OPAMPs.
Modern Bipolar technolgies.
2. Components matching and offset
Deviation from the nominal value, and relative matching of integrated components.
Main sources of mismatch in CMOS and Bipolar technologies.
Matching in a differential stage.
Impact on speed and power dissipation.
Impact on DAC INL and DNL, example of design of a current-steering DAC.
Noise sources in CMOS and Bipolar.
Equivalent input noise generators.
Input noise for basic stages, and opamp.
Noise-power trade off.
Impact on design of sampled system and ADC.
4. CMOS and BiCMOS stages
A short review of the basics: Input stage. Level shift. Slew rate. Frequency compensation. CMRR and its link with offset. PSRR.
Fully differential stages. Common mode feedback network.
5. Output power stages, distortion.
Feedback and distortion.
Bipolar output stages. CMOS output stages.
Power amplifiers basics.
6. Voltage references.
Voltage reference derived by Vbe and Vt.
Bandgap reference: theory and circuits.
CMOS and BiCMOS comparators. Basic structure.
8. Examples of mixed signal design.
Current steering DAC: INL and DNL. Thermometric vs. binary architecture.
ADC: Comparison between pipeline, SAR and Delta sigma.
Advanced techniques and figure-of-merit.