DIGITAL ELECTRONICS
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- Versione italiana
- Academic year
- 2017/2018
- Teacher
- PIERO OLIVO
- Credits
- 9
- Didactic period
- Secondo Semestre
- SSD
- ING-INF/01
Training objectives
- This is the first course of Digital Electronics and it studies the basic elements of a digital system from the electrical point of view, by considering the information as current or voltage.
The main goal of the course consists in providing the basis to tackle the study of complex digital systems and of their interconnections under the constrains imposed by cost, speed, area occupancy, immunity and power consumption.
The main acquired knowledge will be:
basic elements of a digital system form an electrical point of view, considering the information as provided by a voltage or a current;
knowledge related to the analysis of electronic circuits in steady and transient states;
basic knowledge of a CMOS circuit;
basic knowledge to tackle the study of complex digital systems and of their interconnections under the constrains imposed by performances in terms of cost, speed, area occupancy, immunity and power consumption.
Basic knowledge of ADC e DAC and of memory elements;
Basic knowledge of circuit simulation tools.
The basic acquired abilities (that are the capacity of applying the acquired knowledge) will be:
analysis of the behavior of digital circuits in steady and dynamic conditions;
identification of the constrains for the design of digital circuit;
identification of the most suitable ADC/DAC or memory elements for a specific application;
use of simulation programs to analyze digital circuits. Prerequisites
- The following concepts and the knowledge provided by the courses of “Analisi e sintesi dei circuiti digitali (Analysis and synthesis of digital circuits)” and “Teoria dei Circuiti (Circuits Theory)” are mandatory:
basic concepts of mathematics and differential computation;
knowledge of the basic concepts of the physics, especially those related to electromagnetic;
knowledge of the circuit theory: Ohm and Kirchhoff lows and their practical application; methods to analyze electrical circuits in steady and transient states:
knowledge of the logic networks: binary arithmetic; combinational and sequential circuits;
ability in analyzing and designing small digital systems at the logic level. Course programme
- The course forecasts 90 hours of teaching divided in frontal lectures (70 hours) and guided tutorial in the labs (20 hours).
Digital and analog electronics - Digital systems (7.5 hours)
Differences between analog and digital electronics – Operating levels: systems, boards, integrated circuits and different abstraction levels - Basic elements - Digital design evolution: custom, semicustom, FPGA - Signal integrity - Elements of semiconductor physics and technology.
Circuits with passive and actives elements (7.5 hours + 7.5 hours in the laboratory)
Elementary circuits with resistances - Use of Ohm and Kirchhoff laws - Resistive voltage divider – Semiconductor devices – Ideal diode characteristic – Circuits with resistances and diodes – Semiconductor technology
Basic digital circuits’ properties (5 hours)
Figure of merits (cost, performance, reliability,....) - I/O characteristics - Dynamic characteristics - Power consumption.
CMOS Circuits (7.5 hours)
Elements of MOS transistor operations - CMOS inverter - Relay-like behavior - Static characteristic, Logic threshold, geometric dimensions, power consumption - CMOS and FCMOS gates
Switching and signal transmission (10 hours)
Different problems in boards and chips - Capacitive load - Transients in CMOS circuits - CMOS circuits dimensions – Comparison between NAND and NOR CMOS - Distributed RC networks - Buffers -Transmission lines (circuit model for transmission lines, discontinuity) – Terminations - Fan-out lines and bus.
Noise in digital systems (5 hours)
Capacitive Crosstalk - Power and ground bouncing - Simultaneous switching - Ohmic drops on power lines - Emerging problems caused by dimension reduction and frequency increase.
Waveform generators (5 hours)
Monostable CMOS – Astable CMOS – Schmitt trigger
ADC and DAC (7.5 hours)
Conversion theory - general properties of signal converters - DAC (binary weighted resistors, R-2R ladder) - ADC (double ramps, counters, successive approximations, flash) - Antialiasing filters - Sample & hold circuits.
Memories (15 hours)
Memories’ characteristics - Memories organization- Decoder - Random Access Memories; SRAM cells; SRAM read/write; DRAM cells; DRAM rear/write; mostly read memories and non-volatile memories: evolution and classification; ROM, EPROM, OTP, EEPROM, FLASH NOR e FLASH NAND. Flotox cells–NOR and NAND architectures – Program/erase and reading of non-volatile memories
Circuit Simulations (12.5 hours)
Introduction to Spice – Practical lessons related to the simulations of simple digital circuits Didactic methods
- The course is organized as follow:
frontal lectures on all the course’s topics;
practice exercises in the Electronics lab concerning the analysis of simple circuits realized with resistances and diodes. Students will be divided in several groups (max 27 students per group) and they will take 3 guided tutorials of 2 hours each. After the guided tutorials the students will have free access to the lab for additional individual tests;
practice exercises in the Computer lab concerning the simulation of simple digital circuits. Students will take 5 guided tutorials of 2 hours each. After the guided tutorials the students will have free access to the lab for additional individual tests. Learning assessment procedures
- The aim of the exam is to verify at which level the learning objectives previously described have been acquired.
The examination is divided in 3 sections that will take place in the same day.
•One test (multiple choice questions or solutions of numeric exercises) based on all the topics tackled in the class or on the basic concepts of the following courses: “Analysis and synthesis of digital circuits” and “Circuits Theory”, with the aim of evaluating how deeply the student has studied the subject and how he is able to understand the basic topics analyzed. This section is selective (the student that does not show a sufficient knowledge of the subject, cannot be admitted to the following sections.) To pass this test it is required to get at least 6 points out of 15. The time allowed for this test is 1 hour. It is not allowed consulting any textbook or using any PC, smart phone, calculator….;
•One simulation of a simple digital circuit by using the SPICE platform, with the aim of understanding if the student has acquired the knowledge to simulate and synthetize digital circuits. To pass this test it is required to get at least 3 points out of 8. The time allowed for this test is 1 hour. It is allowed consulting the pSpice program manual;
•One oral section, where the ability of linking different subjects related to the digital electronics is evaluated, rather than the ability of “repeating” specific topics tackled in the course. To pass this test it is required to get at least 4 points out of 11. Passing the test is a witness of having acquired the knowledge of the methods for the analysis of complex digital systems and their interconnections in the presence of constraints on cost, speed, area occupancy and noise immunity.
The final mark is the sum of the 3 marks.
To pass the exam it is necessary to get at least 18 point out of 33.
Passing the exam is proof of having acquired the ability to apply knowledge relating to technologies for digital signal processing and to analyze the behavior of circuits and digital electronic systems in the different areas of information and communication technology.
If one of the 3 tests is not passed or if the final mark is below 18, it is necessary to repeat all the exam’s sections. Reference texts
- Teacher’s handouts available on the course web page
Specific topics can be further developed in the following texts.
J.M. Rabaey, A. Chandrakasan, B. Nikolic; Digital Integrated Circuits; Prentice Hall, 2nd edition, 2003 (textbook also adopted for the course of “Elettronica dei sistemi digitali”)
W. J. Dally, J. W. Poulton; Digital System Engineering; Cambridge University Press, 1998
