9.18 Sspd_chapter 7_part 5_stick diagrams of cmos gates_concluded

SSPD_Chapter 7_part 5_Stick Diagrams of CMOS Gates_concluded.

7.5.4. CMOS Transmission Gate.

Figure 7.5.4.1 gives the layout of transmission switch and its stick diagram.

Blue- metal 1, Red – Poly-Si, Green – N+diffusion for (E)NMOS; Brown – P+diffusion.

Whenever control I/P ‘C’ = 1, ‘C complement’=0. Both the transistors turn ON and there is full transmission from I/P to O/P.

Whenever ‘C’= 0, ‘C complement’= 1 then both transistors turn ‘OFF’ and the transmission is stopped between I/P and O/P.

7.5.5. CMOS 2-input Multiplexer.

Figure 7.5.5.1 gives the Symbol and the layout of 2-input multiplexer expressed as stick disagram.

The circuit model of the layout is given in Figure 7.5.5.2.

By inspection of the circuit model we see that

when control input C=’1’ then Z = B and

when C= ‘0’ then Z = A.

• Metal Interconnect Layers.

Metal layers are electrically isolated from each other. Electrical contact between

adjacent conducting layers requires contact cuts and vias.