VLSI design considrations...

[lord loh.]

I was just wondering about a VLSI designs....

1. In VLSI design does one work at the gate levels or does one have to bother about every individual transistor / FET ?

2. The TTL gate ICs have totempole output. In case of an IC like a multiplexer IC, which contains AND gates followed by an OR, does each AND gate inside the IC need a totempole output ? Since they supply current to only one OR gate, I do not think it is needed, or is it ?

 

[evandude]

I am currently taking a VLSI design course, so I don't know everything.

but to answer your questions:

1) this depends on the application. For quick designs sometimes designers will throw together pre-made gates and such. But for production run designs, the design is usually taken down to the transistor level.

2) "buffered" output I assume you mean? no, as long as the gates have similarly sized transistors they should not need buffering between gates.