tailieunhanh - Ebook Digital integrated circuits prentice hall: Part 2

(BQ) Part 2 book "Digital integrated circuits prentice hall" has contents: Designing combinational logic gates in cmos, designing sequential logic circuits, coping with interconnect, timing issues in digital circuits. | CHAPTER 6 DESIGNING COMBINATIONAL LOGIC GATES IN CMOS In-depth discussion of logic families in CMOS— static and dynamic, pass-transistor, non-ratioed and ratioed logic n Optimizing a logic gate for area, speed, energy, or robustness n Low-power and high-performance circuit-design techniques Introduction Issues in Dynamic Design Static CMOS Design Cascading Dynamic Gates Ratioed Logic How to Choose a Logic Style? Complementary CMOS Pass-Transistor Logic Designing Logic for Reduced Supply Voltages Dynamic CMOS Design Perspectives Dynamic Logic: Basic Principles Summary Speed and Power Dissipation of Dynamic Logic To Probe Further 229 230 DESIGNING COMBINATIONAL LOGIC GATES IN CMOS Chapter 6 Introduction 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 on combinational logic (or non-regenerative) 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 accomplished 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 a combinational logic portion and a module that holds the state. Example circuits are registers, counters, oscillators, and memory. Sequential circuits are the topic of the next