EECS 247 Lecture 1: Introduction © 2005 H.K. Page 1EECS 247Analog-Digital Interface Integrated Circuits© 2005Instructor: Haideh KhorramabadiUCB Department of Electrical Engineering and Computer SciencesEECS 247 Lecture 1: Introduction © 2005 H.K. Page 2Administrative• Course web page:http://www.eecs.berkeley.edu/~EE247 – All handouts are available on the web• Office hours for Haideh Khorramabadi– Tues./Thurs. 3-4pm @ 485 Cory Hall– Email: [email protected]• Homework is posted on the course website and is due on Thursdays• Midterm exam: 10/20/05EECS 247 Lecture 1: Introduction © 2005 H.K. Page 3Analog-Digital Interface CircuitsDigitalProcessorAnalog/Digital InterfaceAnalog InputAnalog WorldDigital/AnalogInterface0 0 11 1 00 1 01 0 0 11 0 1 00 0 1 0Analog Output•Naturally occurring signals are analogà Need Analog/Digital & Digital/Analog interface circuitsQuestion: Why not process the signal with analog circuits only & thus eliminate need for A/D & D/A?EECS 247 Lecture 1: Introduction © 2005 H.K. Page 4MOSFET Maximum ftversus Time*Ref: Paul R. Gray UCB EE290 course ‘95International Technology Roadmap for Semiconductors, http://public.itrs.netFor MOS (VGS - Vth = 0.5V )75 80 85 90 95 ’00 ‘05 6u3u2u1.5u1u0.8u0.6u0.35u0.25u0.13u0.1u1GHz10GHz100GHzftYear0.18uEECS 247 Lecture 1: Introduction © 2005 H.K. Page 5Digital Signal Processing Characteristics• Direct benefit from the down scaling of VLSI technology • Not sensitive to “analog” noise• Enhanced functionality & flexibility• Amenable to automated design & test• “Arbitrary” precision• Provides inexpensive storage capabilityEECS 247 Lecture 1: Introduction © 2005 H.K. Page 6Analog Signal Processing Characteristics• Has not fully benefited from the down scaling of VLSI technology– Supply voltages scale down accordingly à Reduced voltage swings– Reduced voltage swings requires lowering of the circuit noise to keep a constant dynamic rangeà Higher power dissipation and chip area• Sensitive to “analog” noise• Not amenable to automated design • Extra precision comes at a high price• Availability of inexpensive digital capabilities on-chip enables automatic adjustments to compensate for analog circuit impairments• Rapid progress in DSP has imposed higher demands on analog/digital interface circuitryà Plenty of room for innovations!EECS 247 Lecture 1: Introduction © 2005 H.K. Page 7Cost/Function ComparisonDSP & Analog• Digital circuitry: Fully benefited from CMOS device scaling– Cost/function decreases by ~29% each yearàCost/function 30X in 10 years*• Analog circuitry: Not fully benefited from CMOS scaling– Device scaling mandates drop in supply voltagesàthreaten analog feasibilityàCost/function for analog ckt almost constant or increase• Rapid shift of functions from analog to digital signal processing & hence need for A/D & D/A interface circuitry*Ref: International Technology Roadmap for Semiconductors, http://public.itrs.netEECS 247 Lecture 1: Introduction © 2005 H.K. Page 8Example: Digital Audio• Goal-Lossless archival and transmission of audio signals• Circuit functions:– Preprocessing• Amplification• Anti-alias filtering– A/D Conversion• Resolutionà16Bits• Sig. bandwidthà41kHz– DSP• Storage• Processing (e.g. recognition)– D/A Conversion– Postprocessing• Smoothing filter• Variable gain amplificationAnalog PostprocessingD/AConversionDSPA/D ConversionAnalog PreprocessingAnalog InputAnalog OutputEECS 247 Lecture 1: Introduction © 2005 H.K. Page 9Example: Typical Dual Mode Cell PhoneContains in integrated form:• 4 Rx filters• 4 Tx filters• 4 Rx ADCs• 4 Tx DACs• 3 Auxiliary ADCs• 8 Auxiliary DACsTotal: Filters à 8ADCs à 7DACs à 12Dual Standard, I/QAudio, Tx/Rx powercontrol, Battery chargecontrol, display, ...EECS 247 Lecture 1: Introduction © 2005 H.K. Page 10Areas Utilizing Analog/Digital Interface Circuitry• Communications– Wireline communications• Telephone related (DSL, ISDN, CODEC)• Television circuitry (Cable modems, TV tuners…)• Ethernet (Gigabit, 10/100BaseT…)– Wireless• Cellular telephone (CDMA, Analog, GSM….)• Wireless LAN (Blue tooth, 802.11a/b/g…..)• Radio (analog & digital), Television• Computing & Control– Storage media (disk drives, digital tape)– Imagers & displays• Instrumentation– Test equipment– Physical sensors & actuators• Consumer Electronics– Audio (CD, DAT)– Automotive control, appliances, toysEECS 247 Lecture 1: Introduction © 2005 H.K. Page 11UCB Analog Courses EECS 247 - 240 - 242• EECS 247– Filters, ADCs, DACs, some system level– Signal processing fundamentals– Macro-models, large systems, some transistor level, constraints such as finite gain, supply voltage, noise, dynamic range considered– CAD Tools à Matlab, SPICE• EECS 240– Transistor level, building blocks such as opamps, buffers, comparator….– Device and circuit fundamentals– CAD Tools à SPICE• EECS 242– RF amplification, mixing– Oscillators– Exotic technology devices – Nonlinear circuitsEECS 247 Lecture 1: Introduction © 2005 H.K. Page 12Material Covered in EE247• Filters – Continuous-time filters• Biquads & ladder type filters• Opamp-RC, Opamp-MOSFET-C, gm-C filters• Automatic frequency tuning– Switched capacitor (SC) filters• Data Converters– D/A converter architectures– A/D converter • Nyquist rate ADC- Flash, Pipeline ADCs,….• Oversampled converters• Self-calibration techniques• Systems utilizing analog/digital interfaces– Wireline communication systems- ISDN, XDSL…– Wireless communication systems- Wireless LAN, Cellular telephone,…– Disk drive electronics– Fiber-optics systemsEECS 247 Lecture 1: Introduction © 2005 H.K. Page 13Introduction to Filters• Filtering à Frequency-selective signal processing– It’s the most common type of signal processing– Examples:• Extraction of desired signal from many (radio)• Separating signal and noise• Amplifier bandwidth limitationsω()ωjHIdeal Low-Pass Brick Wall Filter()ωjHωMore Practical FilterEECS 247 Lecture 1: Introduction © 2005 H.K. Page 14Simplest FilterFirst-Order RC Filter (LPF1)Steady-state frequency response:outinooV(s)1H(s)sV(s)11with 2100kHzRCωωπ==+==×EECS 247 Lecture 1: Introduction © 2005 H.K.
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