CMOS NAND Gate :
The truth table of the simple two input NAND gate is shown in Table .
From the Table, it is observed that the output function F is low only when all the inputs A and B are high. Construction of PDN :
The PDN of two input NAND gate is shown in
Figure below. It consists of series combination of NMOS transistors that conduct when both A and B are high and pulls the output 'F' to low.
Construction of PUN :
The PUN is the dual network of PDN and it consists of parallel combination of two PMOS transistors as shown in Figure below.
This means that F is pulled to logic high if A = 0 or
B = 0 which is equivalent to F = â€“â€“â€“â€“â€“â€“A ïƒ— B.
Construction of CMOS 2 input NAND gate :
The complete CMOS NAND gate is as shown in Figure below, which is a combination of PUN and PDN.