NAND Gate (MOSFET)

I will explain about NAND Gate and how to make NAND Gate with MOSFET

 

Nand Gate is a logic gate that has False (0 =”zero”) output if the all inputs are True (1=”one”).

 

Algebra Function, Symbol, and Truth Table

  •  F= (A.B)’

    NAND Gate

    NAND Gate 2 input

image source : http://3.bp.blogspot.com/_2f2l7iCFZ88/S9_TjkaXD1I/AAAAAAAAAC0/1yKCs0BzHEY/s1600/nand.gif

Now I will show you how to make NAND Gate with MOSFET. I make and simulate this circuit with LTSPICE software.

 

 

  • NAND Gate 2 Input

            Firstly, in PMOS Configuration,  We need to add 2 PMOS and connect those in parallel with VDD connect to each of the drain. Then, connect each of the Gate output with the line that connect Drain and VDD in their respective PMOS. Connect the First PMOS’ Source to the Second PMOS’ Source.

Parallel PMOS

           Secondly, in CMOS Configuration,  We need to add 2 NMOS and connect those in cascade with the first Source connect to the Drain and the second Source connect to the ground. Connect each of the NMOS output gate to the ground.

Cascade NMOS

           Finally, We connect the first input (A) to the Gate inputs of the first PMOS and NMOS. Then We connect the second input (B) to the second PMOS and NMOS gates. After that, We connect the first Drain to the Second NMOS Source. Then, add a line from the tri-section to the output. Now we have a NAND Gate with 2 input!

NAND Gate

You can simulate your circuit in LTSPICE by give the inputs and VDD the source that you want.

If you want to make more than 2 inputs you can just add another PMOS and NMOS and connect those in the next PMOS(Parallel)  and NMOS (Cascade).

P.S : Now, I only can explain about designing the gate but not about the theory how to calculate the circuit because I haven’t studied it yet.

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~ by L on July 5, 2011.

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