1 SELECTION OF A GATE ARRAY CELL COMES DOWN TO SELECTING THE NUMBER...

8.1 Selection of a gate array cell comes down to selecting the number of transistors to place

in series in a cell, remembering that if a cell uses less transistors, then the extra tran-

sistors are not utilized. We can categorize individual gates by the number of series

transistors they require (i.e. an n-strip below a p-strip, as in Figure 8.28). The fol-

lowing table summarizes the usage in particular chip in the exercise:

Cell Type Series transistors Circuit Percentage

D-latch 5 Figure 7.17f with

clock inverter

D-flipflop 10 Two D-latches