设为首页 - 加入收藏 - 网站地图 我爱嵌入式(www.52embed.com),专注嵌入式开发技术!
当前位置:主页 > 模拟电子 > 正文

模拟设计圣经100条

时间:2015-07-19 20:31 来源:网络 作者:网络 阅读:
翻译中将会给出英语原文,我的翻译,以及一些备注或者个人感悟。时间仓促,水平有限,难免出错。还望看到本文的各位同好们,不吝指正。
最后,感谢原文作者,网上的翻译作者,以及我的模电老师。
 
(小编感慨:作者花了6小时翻译的模拟设计宝典,快收藏吧~)
 
以下为翻译:
 
1/ Capacitors and resistors have parasitic inductance, about 0.4nH for surface mount and 4nH for a leaded component.
1、电容以及电阻都存在寄生电感。贴片封装的大约有0.4nH,直插式封装大约有4nH
电路元件往往都被视为简化的模型,在低频段这些等效方法没有问题,但是在高频段,这些模型中的电感、电容效应都应该纳入考虑
 
2/ If you don"t want a high bandwidth transistor to oscillate place lossy components in at least 2 of the 3 leads. Ferrite beads work well.
如果一个高带宽三极管发生震荡,那么可以在至少两个引脚中放置损耗元件来消除,磁珠将会是一个不错的选择
 
3/ When taking DC measurements in a circuit and they don"t make sense, suspect that something is oscillating.
对一个电路进行直流测试时,如果不起作用,那么应该考虑是否发生了震荡
 
4/ Opamps will often oscillate when driving capacitive loads.
当驱动容性负载时,运算放大器经常会震荡
 
5/ The base-emitter voltage Vbe of a small signal transistor is about 0.65v and drops about 2mV/deg C. Vbe goes down with increasing temp.
小信号三极管的基-射极电压Vbe大约是0.65V,并且温度每升高一度,此电压下降2mV。
 
6/ Multiply 0.13nV by the square root of the ohmic value of a resistor to find the noise in a 1Hz bandwidth. Then multiply by the square root of the BW in Hz gives the total noise voltage.
将电阻值开方并乘上0.13nV,可以计算得到1Hz带宽内的噪声,再乘上以Hz为单位的带宽的平方根,可以计算得到总噪声电压
 
7/ Johnson noise current goes down with a increase in resistance.
Johnson噪声电流,随着电阻的增加而降低。
Johnson噪声,也称为热噪声。
 
8/ The impedance looking into the emitter of a transistor at room temp is 26Ohm/Ie in mA
三极管在室温下的射极阻抗是26欧姆/毫安
 
9/ All amplifiers are differential in that they are referenced to ground somewhere.
任何一个放大器都是对于某个“地”的差分放大
 
10/ Typical metal film resistor has a temp coef of about 100 ppm/deg C
典型的金属薄膜电阻都有一个大约为100 ppm/deg C的温度系数
 
11/ The input noise voltage of a quiet op amp is 1nv/sqrt(Hz) but there are plenty available with 20nV/sqrt(Hz). Op amps with bipolar front-ends have lower voltage noise and higher current noise than those with FET front-ends
低噪声运算放大器的输入噪声可以是1nv/sqrt(Hz),但是更为常见的是20nV/sqrt(Hz)。双极型运算放大器拥有比场效应管更低得电压噪声和更高的电流噪声。
 
12/ Using an LC circuit as a power supply filter can actually multiply the power supply noise at the filter"s resonant frequency. Use inductor with low Q to overcome this.
使用LC电路作为电源的滤波器,将会增加电源谐振频率上的噪声。使用低Q值的电感可以有效克服这个问题。
 
13/ Use comparators for comparing and op amps for amplifying and don"t even think of mixing the two.
使用比较器作比较用,使用放大器作放大用,不要指望可以混用这两个!
 
14/ Ceramic caps with any other dielectric other than NPO should only be used for bypass applications.
除了NPO以外的瓷片电容,都只能够作为旁路电容使用。
NPO是一种最常用的具有温度补偿特性的单片陶瓷电容器。它的填充介质是由铷、钐和一些其它稀有氧化物组成的。
 
15/ An N-channel enhancement-mode FET needs +ve voltage on the gate-source to conduct form drain-source.
N沟道增强型场效应管,需要施加正的门极-源极电压,才能来控制漏极-源极之间的导通。
 
16/ Small signal JFETS work very well as low-leakage diodes by connecting drain & source together in log current-to-voltage converters and low leakage input protection. Small signal bipolars with b-c tied together will also make nice low-leakage diodes.
JFETS短接源漏极在小信号电流-电压转换和输入保护方面具备和低泄漏二极管媲美的特性,小信号测量中晶体管B-C极短接也相当于一个优异的低泄漏二极管。
 
17/ With low pass filter use Bessel for least amount of overshoot in the time domain, and Cauer (or elliptic) for fastest rolloff in the freq domain.
设计低通滤波器时,贝塞尔滤波器在时域中拥有最小的超调量,椭圆滤波器在频域中有最快的高频衰减特性。
 
18/ dB is always 10 times the log of the ratio of 2 powers. 
分贝是20*lgX
 
19/ At low frequencies, the current in the collector of a transistor is in phase with the applied current at the base. At high frequencies the current at the collector lags by 90deg. You must appreciate this simple fact to understand high frequency oscillators.
在低频段,三极管集电极电流与基极电流同相位,在高频段,集电极电流滞后90度。必须谨记这个简单的原则,以此帮助你更好地理解高频振荡。
 
20/ The most common glass-epoxy PCB material (FR4) has a dielectric constant of about 4.3 To make a trace with a characteristic impedance of 100 Ohm, use a trace thickness of about 0.4 times the thickness of the board with a ground plane on the opposite side. For a 50Ohm trace make it 2 times the thickness.
PCB应用最普通的玻璃钢(FR4)材料的介质常数大约为4.3,印制版线为得到100欧的特征阻抗需要的线宽为PCB板(背面覆铜)厚度的0.4倍,50欧的阻抗需要线宽为板后的2倍。
老实说,这句话没看懂。。。。。。(翻译基本照搬了参考的那篇翻译)
 
21/ If you need a programmable dynamic current source, find out about operational transconductance amps. Most of the problem is figuring out when you need a programmable dynamic current source.
当你运用跨导运放做可编程电流源时,会出现很多问题。
 
22/ A CMOS output with an emitter follower can drive a 5V relay nicely as the relays normally have a must-make spec of 3.5V. This saves power and require no flyback components.
CMOS配合一个射极跟随器可以很好地驱动一个5V的继电器(需要是驱动电压3.5V以上的继电器)。这样不仅减小功耗,还能够节省反馈元件。
 
23/ Typical thermocouple potential is 30uV/degC. Route signals differentially, along the same path, avoid temp gradients. DPDT latching relays won"t heat up when multiplexing these signals.
典型的热电偶电位是30uV/degC。布线时差分通路需要走相同的路径,避免不同位置的温度梯度。双刀双掷开关在切换信号时,可以避免切换过程中的热量对热电偶产生影响。
 
24/ You SHOULD be bothered by a design that looks messy, cluttered or indirect. This uncomfortable feeling is one of the few indications that there"s a better way.
你可能会直接或者间接感到电路设计混乱不堪,这种让你不舒服的感觉是一种宝贵的暗示:你的电路还有更好的设计方法。
 
25/ Avoid drawing any current from the wiper of a potentiometer. The resistance of the wiper contact will cause problems (local heating, noise offsets etc.)
尽量避免从电位器的抽头处获取电流。电位器的阻抗可能会造成一些问题(比如局部热效应,噪声,偏置等等)。
 
26/ Most digital phase detectors have a deadband where the analog output does not change over the small range where the 2 inputs are coincident. This often-ignored fact has helped to create some very noisy PLL"s (Use a high val bleeding resistor to always ensure current flow in the deadband)
大多数数字数字鉴相器存在一个死区,即为在一个很小的范围内(双端输入相同时),模拟输出不改变。这个常常被忽视的现象会导致锁相环噪声过大。(用一个高阻值的泄漏电阻来保证电流能够注入死区)。
 
27/ The phase noise of a phase-locked VCO will be at least 6dB worse than the phase noise of the divided reference for each octave between the comparison frequency and the VCO output frequency. Avoid low-comparison frequencies.
锁相的压控振荡器的相位噪声至少比在比较频率端和输出频率端有分开参考的相位噪声差上6分贝,避免使用低比较端频率。
实话实说,这句话翻译起来很绕口,本人也没有用过VCO。纯粹字面翻译,求高手指教。
 
28/ You can almost always determine the leads of a bipolar transistor with an ohm meter. b-e and b-c junctions will measure like a diode with the b-c junction reading slightly lower than the b-e junction when forward biased.
你总是可以通过一个欧姆表(万用表电阻档)来确定三极管的各个引脚。B-E,B-C端都可以看做是一个二极管。在正向偏置时,B-C端读数会略小于B-E端。
 
29/ For low distortion, the drains (or collectors) of a differential amp"s front-end should be bootstrapped to the source (or emitter) so that the voltages on the part are not modulated by the input signal.
为了低失真,差分放大器的漏极(或者集电极)应该被自举(是不是那么翻译不是很确定)到源极(或者射极),这样电压就不会被输入信号所干扰。
 
30/ If your design uses a $3 op amp, and you will be making a thousand of them, you have just spend $3000. Are you smart enough to figure out how to use a $.30 op amp instead?
如果使用一个3美元的放大器,如果生产1000个,就是3000美刀。想一想,能否使用一个30美分的放大器?
成本是模电工程师不得不考虑的一个问题。虽然电子元件单个都不是什么昂贵的东西,但是乘上一个数量,就不是开玩笑的了。
 
31/ The Q of an LC tank circuit is dominated by the losses in the inductor in terms of series R. Q=omega.L/R 
LC震荡电路的品质因数由对于电阻而言的电感损耗来决定(这里是直译,不清楚对不对)。Q=w*L/R。
 
32/ Leakage current doubles for every 10degC increase in temp.
温度每升高10度,漏电流增加一倍。
 
33/ When inputs to most JFET op amps exceed the common-mode range for the part, the output may reverse polarity. This artifact will haunt the designers of these parts for the rest of their lives, as it should!
当JFET的输入值超过其正常工作的范围时,输出极性会相反。设计师会在其今后生涯中经常遇到这种假象。(有种阴魂不散的感觉啊)
 
34/ Understand the difference between "make-before-break" and "break-before-make" when you specify switches.
选择开关时,弄清楚“先断后接”以及“先接后断”的不同区别。
 
35/ 3 Terminal voltage regulators in the TO-220 packages are wonderful parts. They are cheap, rugged, thermally protected and very versatile. Use them virtually any place where you need a protected power transistor. They also make nice AM power-modulators.
TO-220封装的三段稳压器件是非常出色的元器件。他们便宜、耐用、有热保护功能,并且能够适用于各种用途。当你需要一个被保护的电力晶体管时,你时常可以看到他们的存在,他们也可以构成性能优秀的功率调幅器。
TO-220系列,比如常用的三端稳压,LM78系列,LM79系列,做模拟设计都知道的东西。
 
36/ Use step recovery diode where you need fast edges under 100pS (hot-carrier is even faster)
当你需要快速跳变沿低于100pS的场合,可以考虑使用阶跃恢复二极管。(热载流子会更快一些)。
 
37/ The old 723 regulator is still one of the lowest noise regulators around! (2.5uVrms 100Hz-10k)
老当益壮的723稳压器仍然是噪声最低的稳压器件之一(2.5uVrms 100Hz-10k)
 
38/ You can make a very simple oscillator with one diac, cap and a resistor.
你可以用一个双向触发晶体管,电容,电阻构成非常简单的触发器
 
39/ NPN transistors are normally superior to their PNP counterpart in performance.
NPN三极管一般情况下优于其对应的PNP型
40/ Typical spec in some databooks should read "Seen it once". Always work with the worst spec of the part when doing a design.
对于一些DATASHEET中提供的所谓“典型参数”,我们只要看看就可以了,设计的时候,永远考虑最坏的情况。
 
41/ Don"t just copy circuits from application notes without understanding completely how it operates, and the reason for the choice of values.
千万不要不知所以然地照抄电路,而不理解其工作原理以及参数选取的准则。
 
42/ Dealing with crystals, make sure you understand the difference between series and parallel resonant. In a circuit, crystal frequency can generally be slightly lowered by placing a inductor in series and increased by a capacitor in series.
对于晶振,请确保你明白串联谐振和并联谐振的区别。在电路中,串联一个电感会稍稍降低晶振频率,而串联一个电容则会微微增加其频率。
 
43/ Power MOSFETS on-resistance will have a -ve temp coef and not +ve at low current levels. This is important to remember when paralleling devices.
电力MOSFET导通电阻在低温时,拥有负温度系数,对于并联器件,这一定尤为重要。
 
44/ Lowest noise figure of a RF transistor is not normally where the input is perfectly matched.
射频晶体管的最低噪声往往不是其输入信号完美匹配的时候。
没用过射频晶体管,翻译可能有问题。
 
45/ Many un-stable RF devices can be made stable by loading the input or the output by a simple resistor, either in series or parallel.
很多不稳定的射频设备可以通过在输入或者输出端串联或者并联一个电阻负载来使其稳定。
 
46/ You trade gain for bandwidth.
增益和带宽,不可兼得。
意译,总之增加了带宽,增益往往就减小了。
 
47/ Push-pull power invertors using bipolars are risky and can saturate the core because of hysteresis stepping (use power fets)
推挽式功率转换器,使用双极型晶体管是非常冒险的,并且滞后阶跃会使其饱和。(应当使用POWER FET)
后半句的翻译有待推敲。
 
48/ The Al value of a core will increase up to 50% or more under current transients.
在电流突变时,磁芯的电感系数会增加50%或者更多。
 
49/ Be aware of leakage inductance when switching. V=L(dI/dt)
当切换开关时,注意漏电感。 V=L(dI/dt)
 
50/ The harder you turn-on a power transistor, the longer it will take to turn off.( the part where you burn the joules in the device)
越猛力地导通电力晶体管,其关断时间也就越长(设备中你用来消耗能量的那部分)
 
51/ Always remember the Miller guy.
永远记住米勒这个家伙(米勒效应)
52/ In fault-finding a circuit, don"t overlook the obvious. (is there power?)
在检查电路的过程中,永远不要忽视那些显而易见的东西。
阴沟里翻船还是很常见的事情
 
53/ What is a ground loop, and how to avoid it.
接地回路是什么?如何避免它?
 
54/ 120 is a better number than 240 when using LM3XX type adjustable regulators.
在使用LM3XX系列的可调稳压器件时,120是一个比240更好的数字。
以 下这句摘录自网络上找到的那篇翻译:像LM317要求的最小输出电流是5ma,所以一般推荐1.25V处使用240欧姆调压电阻,这样保证空载时也满足最 小电流要求。 使用120欧姆电阻空载电流更大可能在电压精度,负载调整率上比240欧姆更好(10ma效果好于5ma,再大效果就差不多了)
 
55/ The lower comparator in the old 555 may have quite a long storage time.
老式555触发器中的低端比较器,有很长的存储时间
 
56/ ZERO-ESR caps may do more harm than good.
零等效串联电阻的电容可能弊大于利。
 
57/ A correctly configured audio power amplifier will give more distortion in Class-AB, not less, because of the abrupt gain changes inherent in switching from A to B every cycle.
甲乙类音频功率放大器会有更大的失真,因为在甲、乙类切换时,其增益的突变。
 
58/ Be a STAR when it comes to ground matters.
当涉及接地问题的时候,请使用星形连接。
 
59/ Know when you need to use a Zobel network.
能够知晓何时需要一个Zobel网络。
以下一段摘录自意法半导体工程师的某篇文章:Zobel网络也叫Boucherot单元,它基本上是一个串联的电阻-电容(R-C)网络。这种网络能在工作频率范围内使负载对放大器的输出更加阻性,从而增加稳定系数。
 
60/ Use current mirrors and mirror your current.
使用镜像电流源反映你的电流。
 
61/ Heatsink eff decreases with height above sealevel.
散热器的效率随着离开所需散热平面的高度增加而减小。
 
62/ A matt-black heatsink is much better than a shiny one.
一个亚光黑色的散热器比一个闪闪发光的来得更好
 
63/ Ignoring secondary breakdown can be costly.
忽视二次击穿的代价很昂贵!
 
64/ Understand fuses and fuse ratings, fast and slow. Do you know when to use a semiconductor-fuse?
理解熔丝和熔丝等级,反应快还是慢。你是否知道何时需要用到一个半导体熔丝?
这个我还真不知道,求教。。。
 
65/ Charge balancing resistors are a must when stacking serie-parallel high voltage capacitor banks.
串并联高压电容器,必须设置充电平衡电阻。
 
66/ You must understand DC-restoration otherwise you will have a hard time designing Z-modulation in CRT circuits.
你必须理解直流恢复,不然在设计CTR Z调制电路时,就会捉襟见肘。
 
67/ Display 6 vert div low freq on a scope, increase the freq (make sure the source is constant amplitude) until display drops to 4.2 div. That is the true 3dB BW of the scope. (scope-source impedance should be matched)
在示波器上用6格来显示低频段幅值。增加频率(确保信号源频率连续可调),直到幅值降为4.2格时,此时就是真正的-3dB点。(确保输入阻抗匹配)
6*0.7=4.2,这方法挺好,以前没有想到过。那么这样说,如果一开始用5格,当3.5格的时候不是更好观测么。
 
68/ Doing a measurement with your DMM in the ACV position on your DC circuit will give a quick indication of any excess ripple on the supply when you don"t have a scope at hand.
当你的手头没有示波器的时候,数字万用表的交流档可以帮助你读出直流源的纹波大小。
 
69/ Dly timebase on a scope is very useful once you figured out when, why and how to use it.
示波器上的触发延时实际上非常有用,一旦你掌握了何时、为何、如何使用它。
 
70/ Know what to expect before you measure, otherwise any measurement is meaningless.
在测量之前,你要明白什么是你希望测量得到的(数据或者波形),不然任何测量都是毫无意义的。
 
71/ Op amps. Output will swing in the direction that will force the inv-input level to try come closer to the non-inv input level.
运算放大器,输出会向着某方向偏移,该方向会促使反向输入端向同向输入端靠近。
 
72/ Understand virtual ground, slew-rate, CMRR and PSRR. (CMRR decrease with increase in freq)
理解虚地、电压转换速率(摆率)、共模抑制比、电源抑制比(共模抑制比随着频率上升而减小)
 
73/ Making measurements near a spec-analalyzer"s noise floor will give 3dB errors.
在频谱分析仪噪声层附近测量会引入3分贝的误差。
 
74/ Understand the phase-noise limitations of the analyzer when making such measurements on oscillators.
测量振荡器时,理解仪器的相位噪声限制。
 
75/ In a LC oscillator add some C with -ve temp coef to cancel the +ve temp coef of the L for min drift with temp.
在LC震荡电路中,加入具有负温度系数的电容来抑制由于具有正温度系数的电感而引入的温漂。
 
76/ Less drift will result from making C with a few parallel caps, to reduce the heating effect of the oscillating current when spread out over a larger plate area.
为了降低震荡电流在通过较大平面区域时候产生的热效应,一些并行电容可以减少漂移。
这句话也纯粹字面翻译,不是很懂。
 
77/ You will get more tuning range with the same LC combination in a Clapp than in a Colpitts circuit.
同一对LC组合,Clapp电路可以获得比Colpitts电路更大的调谐范围。
Colpitts振荡电路,也称为电容三点式振荡器。
 
78/ High-Q tuned LC filters will have more insertion loss.
高Q值的LC滤波器会有更大的接入损耗。
 
79/ Williams"s Rule (Guru at Linear Tech) for precision op amp circuits: " Always invert (except when you can"t)"
精密放大器的威廉姆法则(来自Linear Tech的权威级人物):永远反向,除非你做不到。
 
80/ Cuk is not a kind of locomotive.
Cuk斩波电路,并不能提高带负载能力。
Locomotive原意是机车。
 
81/ If you don"t know how to make a design better, find out what makes it worse.
如果你不知道如何将一个设计做得更好,那么尝试去寻找什么让其变得更糟。
 
82/ Sometimes you know just enough to be dangerous.
有的时候,你的经验会将你带入歧途。
 
83/ Impedance will reflect back as the square of the turns ratio.
阻抗会以扎数比平方反射回去。
这个,学过《基础电路》《电路理论》这类课程的人,一定做过这道题目吧!
 
84/ If you could design a component with the characteristics of a finger it could cure many design problems and you will be rich.
如果你可以用手指的特点来设计一个原器件,那么你能够解决很多问题,并且赚很多银子。
这句话估计也是有啥特殊含义?这里援引网络上看到的那位译者的理解:(我理解的是,如果你有徒手设计计算一个元件的功力了,就进阶为高手了)
 
85/ Get nervous when the customer you are trying to help doesn"t even have a scope.
当你想帮助的顾客连一个示波器都没有(意思应该是遇上一个彻彻底底门外汉吧),那么你要当心了。
 
86/ Specs quoted by reps always exceed those by Engineering.
推销人员给出的参数规格总是优于工程师给出的
销售的不靠谱,王婆卖瓜自卖自夸,那简直是一定的。
 
87/ A bad (Engineer) workman always blames his tools.
一个糟糕的工程师总是怪罪自己的工具
 
88/ Don"t believe everything that a SPICE program spits out.
千万不要相信SPICE的仿真结果。
何止SPICE,MULTISIM,PROTUES等等仿真软件很大程度不靠谱。尤其是频率一高。
 
89/ It is easy to get the color code of a 1kOhm and 12Ohm resistor mixed up when you are in a hurry.
当你在情急之中,很容易读错1K欧姆电阻和12欧姆电阻的色环。
1K的色环电阻是:棕黑红+误差环。12欧姆色环电阻是:棕红黑+误差环
 
90/ I bet one could write a thesis about the ability of probes to get tangled-up on a bench.
我打赌,一个能够写出一篇关于探针能力的人,在工作中会非常纠结。
 
91/ DMM can upset sensitive circuits from noise generated inside it.
数字万用表内部所产生的噪声可能会干扰到敏感的电路。
 
92/ When probing directly on a crystal of a uP, use 10kOhm or so resistor in series with the probe tip to prevent loading from stopping the osc.
当直接用示波器探针测量晶体时,串接一个10K欧姆左右的电阻以防外部负载干扰到晶体的震荡。
 
93/ It is easier to see what is happening on the ports using a scope when you trigger one chan against the cpu clock.
当你用CPU时钟反向触发示波器时,你更容易看出端口到底发生了什么(问题)。
 
94/ National once made a bad op amp many years ago that some Engineers referred to it as "Jelly Beans"
国家半导体曾经在多年前生产过一枚坏的运算放大器,一些工程师称其为“果冻豆”
可能是文化上的事情,我没能看出笑点在哪里。不过JELLY BEANS确实挺好吃的。
 
95/ The moment you can start to notice distortion on an oscilloscope it is already way past being acceptable.
当你开始注意到示波

(责任编辑:admin)

顶一下
(0)
0%
踩一下
(0)
0%
发表评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。