1. Penn ESE370 Fall2014 -- DeHon 1 ESE370: Circuit-Level Modeling, Design, and Optimization for Digital Systems Day 22: October 22, 2014 Pass Transistor Logic

2. Teaser What does this do? Penn ESE370 Fall2014 -- DeHon 2

3. Previously Penn ESE370 Fall2014 -- DeHon 3

4. Impact of Capacitance Penn ESE370 Fall2014 -- DeHon 4

5. Today Pass Transistor Circuits C diff >0 Penn ESE370 Fall2014 -- DeHon 5

6. Pass Transistor Penn ESE370 Fall2014 -- DeHon 6

7. Identify Function What function? Penn ESE370 Fall2014 -- DeHon 7

8. Area Compare with CMOS circuit? Penn ESE370 Fall2014 -- DeHon 8

9. Output What is Vout if A=0, B=0? Penn ESE370 Fall2014 -- DeHon 9

10. Output What is Vout if A=1, B=0, notB=1? Penn ESE370 Fall2014 -- DeHon 10

11. Output Is this a restoring gate? Penn ESE370 Fall2014 -- DeHon 11

12. Output What does output look like (DC transfer)? –(B=1, notB=0, sweep A, notA=CMOS inv(A)) Penn ESE370 Fall2014 -- DeHon 12

13. Pass TR transfer (B=1) Penn ESE370 Fall2014 -- DeHon 13

14. CMOS Inverter Transfer Penn ESE370 Fall2014 -- DeHon 14

15. Reasonable Input to CMOS Inverter? Penn ESE370 Fall2014 -- DeHon 15

16. Pass tr xor2 with inv restore Penn ESE370 Fall2014 -- DeHon 16

17. Compare CMOS Is this a fair comparison? Penn ESE370 Fall2014 -- DeHon 17

18. Required to use? What need to add to make substitutable with CMOS? Penn ESE370 Fall2014 -- DeHon 18

19. Restore Output Penn ESE370 Fall2014 -- DeHon 19

20. Restore Output Area? (compare to CMOS) Penn ESE370 Fall2014 -- DeHon 20

21. Chain Together Penn ESE370 Fall2014 -- DeHon 21

22. Analyze Stage Penn ESE370 Fall2014 -- DeHon 22

23. Analyze Stage What’s different about this? Penn ESE370 Fall2014 -- DeHon 23

24. Delay B=0, C diff =0? Penn ESE370 Fall2014 -- DeHon 24

25. Equivalent RC Circuit Penn ESE370 Fall2014 -- DeHon 25

26. Circuit Penn ESE370 Fall2014 -- DeHon 26

27. Delay B=1, C diff =0? Penn ESE370 Fall2014 -- DeHon 27

28. Equivalent RC Circuit Penn ESE370 Fall2014 -- DeHon 28

29. Circuit Penn ESE370 Fall2014 -- DeHon 29

30. Circuit What’s different about this? Penn ESE370 Fall2014 -- DeHon 30

31. C diff >0 Penn ESE370 Fall2014 -- DeHon 31

32. Contact/Diffusion Capacitance C j – diffusion depletion C jsw – sidewall capacitance L S – length of diffusion Penn ESE370 Fall2014 -- DeHon 32 LSLS

33. Impact of Capacitance Penn ESE370 Fall2014 -- DeHon 33

34. Inverter Delay Delay driving another inverter? –Include Cdiff=  Cgate Penn ESE370 Fall2014 -- DeHon 34 W=1

35. Delay B=1, C diff =  C g ? Penn ESE370 Fall2014 -- DeHon 35

36. Equivalent RC Circuit? Penn ESE370 Fall2014 -- DeHon 36

37. Equivalent RC Circuit Penn ESE370 Fall2014 -- DeHon 37

38. Bonus (time permit) What does this do? Penn ESE370 Fall2014 -- DeHon 38 A B More examples in book.

39. Idea There are other circuit disciplines Can use pass transistors for logic –Sometimes gives area or delay win Penn ESE370 Fall2014 -- DeHon 39

40. Admin Project –Hopefully done with baseline –Ron office hours today –Get started on design-space exploration and optimization Penn ESE370 Fall2014 -- DeHon 40