文档介绍：CHAPTER
6
BINATIONAL
LOGIC GATES IN CMOS
In-depth discussion of logic families in CMOS—
static and dynamic, pass-transistor, non-ratioed and ratioed logic
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Optimizing a logic gate for area, speed, energy, or robustness
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Low-power and high-performance circuit-design techniques
Introduction Issues in Dynamic Design
Static CMOS Design Cascading Dynamic Gates
CMOS Perspectives
Ratioed Logic How to Choose a Logic Style?
Pass-Transistor Logic Designing Logic for Reduced Supply
Voltages
Dynamic CMOS Design
Dynamic Logic: Basic Principles Summary
Speed and Power Dissipation of To Probe Further
Dynamic Logic
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230 BINATIONAL LOGIC GATES IN CMOS Chapter 6
The design considerations for a simple inverter circuit were presented in the previous
chapter. Now, we will extend this discussion to address the synthesis of arbitrary digital
gates such as NOR, NAND and XOR. The focus is binational logic (or non-regen-
erative) circuits; this is, circuits that have the property that at any point in time, the output
of the circuit is related to its current input signals by some Boolean expression (assuming
that the transients through the logic gates have settled). No intentional connection between
outputs and inputs is present.
This is in contrast to another class of circuits, known as sequential or regenerative,
for which the output is not only a function of the current input data, but also of previous
values of the input signals (Figure ). This is plished by connecting one or more
outputs intentionally back to some inputs. Consequently, the circuit “remembers” past
events and has a sense of history. A sequential circuit includes binational logic por-
tion and a module that holds the state. Example circuits are registers, counters, oscillators,
and memory. Sequential circuits are the topic of the next Chapter.