6 002 CIRCUITS AND ELECTRONICS Digital Circuit 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 13 Review vI vI VI vC R C t 0 vC 0 VO vC VI VO VI e t RC 1 vC VI time constant RC t VO RC 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 13 Let s apply the result to an inverter B A X First rising delay tr at B VS VS A vA 5V 0 1 0 at A B CGS X t 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 13 First rising delay tr at B VS A VS B vA 5V CGS X 0 1 0 at A t vB 5V ideal observed t 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 13 First rising delay tr at B VS A VS B vA 5V CGS X 0 1 0 at A t 5V VOH rising delay of X vB 0 tr t 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 13 Equivalent circuit for 0 1 at B vI VS RL CGS vI VS vB 0 0 From vB for t 0 1 vB VS 0 VS e t RL CGS Now we need to find t for which vB VOH 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 13 Or vOH VS VS e Find tr VS e t r RL CGS t RL CGS VS VOH VS VOH tr ln RL CGS VS VS VOH t r RL CGS ln VS 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 13 Or vOH VS VS e Find tr VS e t r RL CGS t RL CGS VS VOH VS VOH tr ln RLCGS VS VS VOH t r RL CGS ln VS e g RL 1K VS 5V CGS 0 1 pF VOH 4V t r 1 10 3 0 1 10 12 ln 0 16 ns 5 4 5 RC 0 1 ns 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 13 Falling Delay tf Falling delay tf is the t for which vB falls to VOL Equivalent circuit for 1 0 at B vB 0 VS 5V RL VS CGS RON vB X 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 13 Falling Delay tf Equivalent circuit for 1 0 at B vB 0 VS 5V RL VS RON CGS vB CGS vB X Th venin replacement RTH VTH RTH RL RON VTH RON VS RON RL 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 13 From 1 vB VTH VS VTH e t RTH CGS Falling decay tf is the t for which vB falls to VOL t f VOL VTH VS VTH e RTH CGS or VOL VTH t f RTH CGS ln VS VTH 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 13 t f RTH CGS ln e g RL 1K VS 5V CGS 0 1 pF RTH 10 VOL VTH VS VTH RON 10 VOL 1V VTH 0V t f 10 0 1 10 1 6 ps 12 1 ln 5 RC 1 ps 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 13 For recitation Slow may be better Problem chip pin 2 pin 1 v CL v ideal observed slow So the engineers decided to speed it up RL RON made RL small made RON small 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 13 For recitation Slow may be better Problem chip pin 2 pin 1 v CL v ideal observed slow but disaster v observed expected VIL 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 13 Why Consider Case 1 Demo R1 pin1 R0 ok 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 13 Why Consider Case 2 Demo CP R1 pin1 pin2 R0 R2 crosstalk CP R model for crosstalk v 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 13 Case 3 6 002 expert saw the solution R1 CP R0 R2 slower transitions Detailed analysis in recitation 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 13
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