MOS Circuits: Combination & Sequential - Department of Computer Engineering, Prince of Songkla University

1. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Lecture 4 MOS Circuits

2. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Combination & Sequential

3. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Combination & Sequential

4. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut CMOS logic style

5. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Example NAND gate

6. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut 4-input NAND gate

7. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Example : NOR gate

8. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Complex CMOS gate

9. Vdd And-Or-Invert (AOI) C B A B C Out = A+(B*C) ... A Out B A C Gnd How to add terms? Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Complex gate structures

10. Out = A+(B*C) ... Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut OAI/AOI duality Vdd And-Or-Invert (AOI) C B A B C A Out B A C Gnd How to add terms?

11. Vdd C B Out = A*(B+C) ... A Out B A C Gnd Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Demorgan’s law in action Or-And-Invert (OAI) A B C

12. Vdd C B Out = A*(B+C) ... A Out B A C Gnd Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Demorgan’s law in action Or-And-Invert (OAI) A B C

13. Vdd C B Out = A*(B+C) ... A Out B A C Gnd Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Demorgan’s law in action Or-And-Invert (OAI) A B C

14. Vdd C B Out = A*(B+C) ... A Out B A C Gnd Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Demorgan’s law in action Or-And-Invert (OAI) A B C

15. Out = A*(B+C) ... Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Demorgan’s law in action Vdd Or-And-Invert (OAI) C A B A C B Out A B C What is the Magic command to do this? Gnd

16. Vdd Vdd C B C A B A Out Out A B A C B C Gnd Gnd Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut OAI/AOI duality

17. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Step by step layout XNOR gate • The equation for XNOR is: • f = (a * b) + (a' * b') • using DeMorgan's law on each of the two terms gives: • f = (a'+ b')' + (a + b)' • using DeMorgan's law on the two terms together gives: • f = ((a'+ b') * (a + b))' • This could be directly implemented with a single complementary CMOS gate: the equation is in a simple negated product of sums form. This form can be implemented with the standard Or-And-Invert (OAI) style gate.

18. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Non-inverter input • However, using DeMorgan's law one more time on the left term gives: • f = ((a * b)' * (a + b))’ • This form uses no inverted inputs and can be implemented with two gates a NAND gate and an OAI gate. a b f

19. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Logic Graph

20. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Example CMOS

21. Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut Complex CMOS graph