英譯漢3000字--畢業(yè)設(shè)計(電子)(共6頁)

1、精選優(yōu)質(zhì)文檔-傾情為你奉上Integrated CircuitsThe Integrated Circuit Digital logic and electronic circuits derive their functionality from electronic switches called transistor. Roughly speaking, the transistor can be likened to an electronically controlled valve whereby energy applied to one connection of the va

2、lve enables energy to flow between two other connections.By combining multiple transistors, digital logic building blocks such as AND gates and flip-flops are formed. Transistors, in turn, are made from semiconductors. Consult a periodic table of elements in a college chemistry textbook, and you wil

3、l locate semiconductors as a group of elements separating the metals and nonmetals.They are called semiconductors because of their ability to behave as both metals and nonmetals. A semiconductor can be made to conduct electricity like a metal or to insulate as a nonmetal does. These differing electr

4、ical properties can be accurately controlled by mixing the semiconductor with small amounts of other elements. This mixing is called doping. A semiconductor can be doped to contain more electrons (N-type) or fewer electrons (P-type). Examples of commonly used semiconductors are silicon and germanium

5、. Phosphorous and boron are two elements that are used to dope N-type and P-type silicon, respectively. A transistor is constructed by creating a sandwich of differently doped semiconductor layers. The two most common types of transistors, the bipolar-junction transistor (BJT) and the field-effect t

6、ransistor (FET) are schematically illustrated in Figure 2.1.This figure shows both the silicon structures of these elements and their graphical symbolic representation as would be seen in a circuit diagram. The BJT shown is an NPN transistor, because it is composed of a sandwich of N-P-N doped silic

7、on. When a small current is injected into the base terminal, a larger current is enabled to flow from the collector to the emitter.The FET shown is an N-channel FET, which is composed of two N-type regions separated by a P-type substrate. When a voltage is applied to the insulated gate terminal, a c

8、urrent is enabled to flow from the drain to the source. It is called N-channel, because the gate voltage induces an N-channel within the substrate, enabling current to flow between the N-regions. Another basic semiconductor structure is a diode, which is formed simply by a junction of N-type and P-t

9、ype silicon. Diodes act like one-way valves by conducting current only from P to N. Special diodes can be created that emit light when a voltage is applied. Appropriately enough, these components are called light emitting diodes, or LEDs. These small lights are manufactured by the millions and are f

10、ound in diverse applications from telephones to traffic lights. The resulting small chip of semiconductor material on which a transistor or diode is fabricated can be encased in a small plastic package for protection against damage and contamination from the out­side world.Small wires are conne

11、cted within this package between the semiconductor sandwich and pins that protrude from the package to make electrical contact with other parts of the intended circuit. Once you have several discrete transistors, digital logic can be built by directly wiring these components together. The circuit wi

12、ll function, but any substantial amount of digital logic will be very bulky, because several transistors are required to implement each of the various types of logic gates. At the time of the invention of the transistor in 1947 by John Bardeen, Walter Brattain, and William Shockley, the only way to

13、assemble multiple transistors into a single circuit was to buy separate discrete transistors and wire them together. In 1959, Jack Kilby and Robert Noyce independently invented a means of fabricating multiple transistors on a single slab of semiconductor material. Their invention would come to be kn

14、own as the integrated circuit, or IC, which is the foundation of our modern computerized world. An IC is so called because it integrates multiple transistors and diodes onto the same small semiconductor chip. Instead of having to solder individual wires between discrete components, an IC contains ma

15、ny small components that are already wired together in the desired topology to form a circuit. A typical IC, without its plastic or ceramic package, is a square or rectangular silicon die measuring from 2 to 15 mm on an edge. Depending on the level of technology used to manufacture the IC, there may

16、 be anywhere from a dozen to tens of millions of individual transistors on this small chip. This amazing density of electronic components indicates that the transistors and the wires that connect them are extremely small in size. Dimensions on an IC are measured in units of micrometers, with one mic

17、rometer (1mm) being one millionth of a meter. To serve as a reference point, a human hair is roughly 100mm in diameter. Some modern ICs contain components and wires that are measured in increments as small as 0.1mm! Each year, researchers and engineers have been finding new ways to steadily reduce t

18、hese feature sizes to pack more transistors into the same silicon area, as indicated in Figure 2.2. When an IC is designed and fabricated, it generally follows one of two main transistor technologies: bipolar or metal-oxide semiconductor (MOS). Bipolar processes create BJTs, whereas MOS processes cr

19、eate FETs. Bipolar logic was more common before the 1980s, but MOS technologies have since accounted the great majority of digital logic ICs. N-channel FETs are fabricated in an NMOS process, and P-channel FETs are fabricated in a PMOS process. In the 1980s, complementary-MOS, or CMOS, became the do

20、minant process technology and remains so to this day. CMOS ICs incorporate both NMOS and PMOS transistors. 集成電路集成電路數(shù)字邏輯和電子電路由稱為晶體管的電子開關(guān)得到它們的（各種）功能。粗略地說，晶體管好似一種電子控制閥，由此加在閥一端的能量可以使能量在另外兩個連接端之間流動。通過多個晶體管的組合就可以構(gòu)成數(shù)字邏輯模塊，如與門和觸發(fā)電路等。而晶體管是由半導體構(gòu)成的。查閱大學化學書中的元素周期表，你會查到半導體是介于金屬與非金屬之間的一類元素。它們之所以被叫做半導體是由于它們表現(xiàn)出來的性質(zhì)

21、類似于金屬和非金屬。可使半導體像金屬那樣導電，或者像非金屬那樣絕緣。通過半導體和少量其它元素的混合可以精確地控制這些不同的電特性，這種混合技術(shù)稱之為“半導體摻雜”。半導體通過摻雜可以包含更多的電子（N型）或更少的電子（P型）。常用的半導體是硅和鍺，N型硅半導體摻入磷元素，而P型硅半導體摻入硼元素。不同摻雜的半導體層形成的三明治狀夾層結(jié)構(gòu)可以構(gòu)成一個晶體管，最常見的兩類晶體管是雙極型晶體管（BJT）和場效應晶體管（FET），圖2.1給出了它們的圖示。圖中給出了這些晶體管的硅結(jié)構(gòu)，以及它們用于電路圖中的符號。BJT是NPN晶體管，因為由NPN摻雜硅三層構(gòu)成。當小電流注入基極時，可使較大的電流從集電

22、極流向發(fā)射極。圖示的FET是N溝道的場效應型晶體管，它由兩塊被P型基底分離的N型組成。將電壓加在絕緣的柵極上時，可使電流由漏極流向源極。它被叫做N溝道是因為柵極電壓誘導基底上的N通道，使電流能在兩個N區(qū)域之間流動。另一個基本的半導體結(jié)構(gòu)是二極管，由N型和P型硅連接而成的結(jié)組成。二極管的作用就像一個單向閥門，由于電流只能從P流向N?？梢詷?gòu)建一些特殊二極管，在加電壓時可以發(fā)光，這些器件非常合適地被叫做發(fā)光二極管或LED。這種小燈泡數(shù)以百萬計地被制造出來，有各種各樣的應用，從電話機到交通燈。半導體材料上制作晶體管或二極管所形成的小芯片用塑料封裝以防損傷和被外界污染。在這封裝里一些短線連接半導體夾層和從封裝內(nèi)伸出的插腳以便與（使用該晶體管的）電路其余部分連接。一旦你有了一些分立的晶體管，直接用電線將這些器件連線在一起就可以構(gòu)建數(shù)字邏輯（電路）。電路會工作，但任何實質(zhì)性的數(shù)字邏輯（電路）都將十分龐大，因為要在各種邏輯門中每實現(xiàn)一種都需要多個晶體管。1947年，John Bardeen、Walter Brattain和and William Sh