[SOLVED] How many transistors do I need to design a CMOS XOR gate and 2:1 multiplexer?

[erece]

I am designing cmos logic xor gate and 2:1 multiplexer.
In my design i am using 8 pmos and 8 nmos for 2:1 mux and 6 pmos and 6 nmos for xor gate.
I am using pmos and nmos to implement complement A, means that i am not using complement directly into the circuit.
So , i want to know that is it the minimum no. of transistors used in implementing the above two circuits.
I made the design from the knowledge that pull up network conducts when logic is 1 and pull down nwtwork conducts when logic is 0. please tell if i am wrong.

 

[sharif.shiek]

Re: xor gate using cmos.

Xor Requires minimum 12 transistors

 

[yadavvlsi]

Re: xor gate using cmos.

XOR gate in CMOS can be implemented using minimum of 8 transistors.
http://www.ece.mtu.edu/faculty/goel/EE-3130/CMOS-Circuits.pdf
2:1 MUX implementation.
http://users.ece.utexas.edu/~adnan/vlsi-05/lec1Layout.ppt

 

[abhiverma812]

Re: xor gate using cmos.

Hey,

For making Xor gate you can make use of 8 gates, 4 pmos and 4 nmos using simple relation for XOR= (~A)B+A(~B)
As far as 2:1 MUX is concerned, there are many options. You can use NAND gate, Transmission gates, pass transistor.

Best Regards,
Abhishek

 

[AdvaRes]

Re: xor gate using cmos.

Hi all,
Try this one it has only 6 Transistors.

 

[abhiverma812]

Re: xor gate using cmos.

Hi AdvaRes,

I need to know if the circuit posted by you have good noise margins as with 8 transistors?

BR//
Abhishek

 

[AdvaRes]

Re: xor gate using cmos.

Nice question. But I have not the reply but it is easy to find it. You can compare the 2 circuits using spectreRF.