6 002 CIRCUITS AND ELECTRONICS Inside the Digital Gate Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 Review The Digital Abstraction z Discretize value 0 1 z Static discipline meet voltage thresholds sender VOH VOL receiver VIH VIL forbidden region Specifies how gates must be designed Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 Review Combinational gate abstraction outputs function of input alone satisfies static discipline A B C NAND A 0 0 1 1 B 0 1 0 1 C 1 1 1 0 Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 For example a digital circuit Demo A B A B D C D C A B 3 gates here A Pentium III class microprocessor is a circuit with over 4 million gates The RAW chip http www cag lcs mit edu raw being built at the Lab for Computer Science at MIT has about 3 million gates Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 How to build a digital gate Analogy l ike power supply A li taps s e h c t i ke sw B C if A ON AND B ON C has H20 else C has no H20 Use this insight to build an AND gate Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 How to build a digital gate OR gate A C B Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 Electrical Analogy C B A V Bulb C is ON if A AND B are ON else C is off Key switch device Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 Electrical Analogy equivalent ckt Key switch device control in C 0 in out C in out C 1 3 Terminal device if C 0 else out short circuit between in and out open circuit between in and out For mechanical switch control mechanical pressure Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 Consider VS RL RL VOUT VS VOUT IN C VS C 1 OUT VS VOUT C 0 Truth table for C VOUT 0 1 1 0 VS VOUT C 1 Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 What about VS Truth table for c1 c2 VO 0 0 1 0 1 1 1 0 1 1 1 0 VOUT c1 c2 Truth table for VS VOUT c1 c2 c1 c2 VO 0 0 1 0 1 0 1 0 0 1 1 0 Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 What about can also build compound gates VS D A C D A B C B Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 The MOSFET Device Metal Oxide Semiconductor Field Effect Transistor drain D G gate S source 3 terminal lumped element behaves like a switch G control terminal D S behave in a symmetric manner for our needs Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 The MOSFET Device Understand its operation by viewing it as a two port element out k k c e Ch extboo l the t s interna for it ture iG c u r t s D iDS G vGS vDS S D off G vGS VT G vGS VT S D iDS on S VT 1V typically Switch model S model of the MOSFET Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 Demo Check the MOS device on a scope i DS vDS vGS iDS vGS VT vGS VT vDS iDS vs vDS Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 A MOSFET Inverter VS 5V RL vOUT A B IN A B Note the power of abstraction The abstract inverter gate representation hides the internal details such as power supply connections RL GND etc When we build digital circuits the and are common across all gates Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 Example vOUT 5V vOUT vIN v IN 0V V T 1V 5V The T1000 model laptop desires gates that satisfy the static discipline with voltage thresholds Does out inverter qualify 1 VOL 0 5V VIL 0 9V VOH 4 5V VIH 4 1V sender 5 4 5 V OH receiver 5 4 1 0 9 0 5 VOL 0 0 0 Our inverter satisfies this 1 VIH VIL 0 Cite as Anant Agarwal and Jeffrey Lang course materials for 6 002 Circuits and Electronics Spring 2007 MIT OpenCourseWare http ocw mit edu Massachusetts Institute of Technology Downloaded on DD Month YYYY 6 002 Fall 2000 Lecture 5 E g Does our inverter satisfy the static discipline for these thresholds VOL 0 …
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