Question

1. Mention the guidelines of CMOS ckt design

2.Create the CMOS ckt using (i) truth table (ii) bubble pushing
(iii) Structured method. F=a(b+c)

Answer 1

Guidelines for CMOS circuit design:

1. Use minimum number of transistors to reduce power consumption and cost.
2. Use static CMOS design for low power, high performance and simple implementation.
3. Size transistors carefully to match the rise and fall times of output.
4. Provide proper voltage levels at inputs to prevent short circuits during switching.
5. Use transistor stacking to implement complex gates.
6. Use transmission gates for low power and high speed.
7. Provide adequate noise immunity at inputs.

CMOS circuit design steps:

1.Truth table:

A B C F

0 0 0 0

0 0 1 0

0 1 0 0

0 1 1 0

1 0 0 1

1 0 1 1

1 1 0 1

1 1 1 0

2. Bubble pushing:

F = a'b'c'+ a'b'c + ab'c'+abc

3. Structured design method:

Pull-up network: P1 (a',b'), P2(c')

Pull-down network: N1(a), N2(b), N3(c)

The final CMOS circuit would be:

_____

F o | |

| |

| P1|

||

| |

| P2|

|__|

| |

__| N1|

| |

a

Answer 2

2. The structure method bc the book gives it and I got it right