版图设计噪声与匹配

合集下载

版图的匹配和抗干扰设计

i 1
N
i
s
1 2 i m N 1 i 1
N
匹配设计
• 称均值mδ为系统失配 • 称方差sδ为随机失配 • 失配的分布： • 3δ失配：
| mδ |+3 sδ 概率99.7%
匹配设计
• 失配的原因
– 随机失配：尺寸、掺杂、氧化层厚度等影响元件值的参量的微观波动(fluctuation)
匹配设计
• 晶体管匹配：主要关心元件之间栅源电压（差分对）和漏极电流（电流镜）的偏差
– 栅源电压失配为：
k VGS Vt Vgs1 2k 2 – 漏极电流失配为：
2Vt I D 2 k2 1 I D1 k1 Vgs1
ΔVt, Δk为元件间的阈值电压和跨导之差， Vgs1为第1个元件的有效栅电压，k1, k2为两个元件的跨导
• 降低系统失配的例子
– 一维公用重心设计 – 二维公用重心设计
匹配设计
• 降低系统失配的例子
– 单元整数比(R1:R2=1:1.5) – 均匀分布和公用重心 – Dymmy元件
R1 R2 R1 R2 R1
dummy R1 R2
R2 dummy
匹配设计
• 降低系统失配的例子
– 单元整数比(8:1) – 加dummy元件 – 公用重心布局 – 问题：布线困难，布线寄生电容影响精度
15Ω
4u
匹配设计
• 系统失配例子 ——电容
假设对poly2的刻蚀工艺偏差是0.1um，两个电容的面积分别是(10.1)2和(20.1)2，则系统失配约为 1.1%
20um 20um
10um 10um
匹配设计

用CAD进行声学分析与设计

用CAD进行声学分析与设计声学是研究声波传播和其在各种环境中产生影响的科学。

在建筑设计、音响系统设计以及汽车和航空航天等领域中，声学设计起着重要作用。

而计算机辅助设计（CAD）软件为声学分析和设计提供了强大的工具。

在CAD软件中进行声学分析和设计，可以帮助工程师快速准确地模拟和优化声学系统。

以下将介绍几种常见的声学分析与设计方法。

首先是声场分析。

声场是指特定空间内的声波分布。

在CAD软件中，工程师可以通过建立几何模型来模拟声场的传播和分布。

该模型可以包括建筑物、房间或器件的几何形状和材料参数。

通过设置合适的声源和边界条件，可以计算出声场中声压级、声能分布、回声时间等参数。

这样的分析结果可以帮助工程师评估声学环境的优劣，并优化设计。

其次是声学过程模拟。

在音响系统设计中，CAD软件可以对声波在各种元件和设备中的传播和变化进行模拟。

例如，在扬声器设计中，可以通过CAD软件模拟声波在扬声器腔体和振膜中的传播和谐振特性。

通过调整声学元件的形状和参数，可以实现对音质和频率响应的优化。

此外，CAD软件还可以模拟声波在管道、隔音材料等中的传播过程，帮助优化声学系统的性能。

另外，CAD软件还可以进行声学材料设计和优化。

声学材料的选择和设计对于声学系统的性能至关重要。

通过CAD软件，工程师可以模拟不同材料的声学特性，并评估其对声波的吸收、反射和传导能力。

这使得工程师能够选择合适的材料，以达到声学系统的优化设计目标。

最后，CAD软件还可以进行噪音分析和控制。

噪音是一种令人不快的声音，对人们的健康和生活质量有着重要的影响。

通过CAD软件，工程师可以对噪音源进行建模，并模拟噪音在空间中的传播和衰减过程。

这可以帮助工程师找到噪音来源和传播路径，并采取合适的控制措施，减少噪音对人们的影响。

综上所述，CAD软件在声学分析和设计中具有重要的应用。

它可以帮助工程师模拟声场、模拟声学过程、进行声学材料设计和优化以及进行噪音分析和控制。

IC设计和版图中噪声减小的方法以及floorplan注意事项2

IC设计和版图中噪声减⼩的⽅法以及floorplan注意事项2 Noise Reduction Is Crucial To Mixed-Signal ASIC Design Success (Part II)Floorplanning, I/O placement, pinout, and power-stability issues round out the noise-reduction design problem.by Jerry Twomey IBM MICROELECTRONICSLarge CMOS ASICs and system-on-a-chip designs often contain both analog and digital sections. Combining the two into a mixed-signal IC frequently leads to noise problems. This article, the second in a two-part series, deals with noise-reduction matters affecting the whole IC.As discussed in the first article, engineers should think about addressing noise issues as part of the design process to avoid such difficulties during chip debug ["Noise Reduction Is Crucial To Mixed-Signal ASIC Design Success (Part I)," electronic design, Oct. 30, p. 123]. Dealing with the trouble after the fact can be costly. Complicating the situation is the fact that Spice simulations often don't show many noise problems. Impedance of interconnects, adjacent device coupling, and substrate noise are usually not modeled accurately.Transition switching noise is an RF issue, with a very broad spectrum. At these frequencies, connection inductance and parasitic capacitance become significant factors.Noise coupling is often distributed, with multiple talkers and listeners. Most effective methods of noise reduction include suppression of talkers at the source and use of noise-immune listeners throughout the IC. For our purposes, "noise reduction" refers to both reducing noise sources and using circuits and layouts that make the system less sensitive to noise. Note that including noise immunity in a design doesn't mean larger chips. Done properly, the die area usually doesn't change.Noise-Reduction MethodsNoise-reduction methods can be categorized into four areas: providing low impedance and quiet connections for power, ground, and substrate; designing analog circuits that are less sensitive to noise; reducing or silencing any noise generators; and separating the talker-listeners using proximity separation, separation in frequency, or separation in time.The following is a summary of the previous article, which dealt with noise immunity of internal circuits.Differential circuits and signals provide common-mode noise rejection and less sensitivity to power and ground noise.Limiting circuit bandwidth helps to avoid noise amplification--using just enough bandwidth to get the job done. Wide-bandwidth circuits would amplify undesired system noise as well. Plus, RF filters on analog signals can cut down on parasitic coupling of noise.Reducing the number of external analog signals minimizes opportunities for noise coupling. Using large-amplitude signals directly improves the signal-to-noise ratio.Internally distributed power filtering placed in unused areas, under metal traces, and in similar locations can provide better power stability, especially at high frequencies.Extensive use of grounded substrate contacts, n-well tie-ups, and guard rings (well beyond what design rules require for latch-up protection) will reduce substrate noise.Signal separation and shielding helps to avoid noise coupling through parasitic capacitance. In addition, by using separated analog-digital routing and keeping talker-listener signals apart, noise concerns will improve.The most significant source of noise in most mixed-signal ASICs comes from digital transition switching. Strategies to decrease digital noise generation include minimum drive-strength devices, low-noise logic types, differential output drivers, and limited slew-rate devices.Some analog circuits produce noise due to transition switching. On/off current situations, current and voltage pulses, and any switched step voltages are the items to look for here. Removing these elements, or reducing their effects as a noise generator, will give better noise performance.Following these eight noise-immunity tips for an IC's internal circuits will go a long way toward creating a noise-robust system. Attention then turns to integrating these circuits onto an IC. This includes circuit placement, selection of I/O drivers, pin placements, interconnect issues, and power, ground, and substrate concerns.At high frequencies, the impedance associated with interconnect metal, bond wire, and the package's lead frame can become a significant factor in the stability of internal power/ground. For the digital section, maximizing the number of parallel power/ground pins to reduce impedance should be considered as a starting point.Separating the power/ground connections used for the analog sections from those used for the digital areas will improve the isolation of the power supplies. Analog cells that use large current transients (large di/dt) should be considered for independent power/ground interconnects. If possible, consider redesign of these circuits to a current-steering method to avoid current transients on the power supply.Fig. 1Separating the analog and digital power/groundconnections will improve isolation of the powersupplies. The configuration in (a) is usually themost problematic method for power stability. Asomewhat better layout is shown in (b). The circuitin (c) is the best because it provides no direct pathfor noise due to digital transition switching on theanalog circuit power.Figure 1 (above) illustrates the possible interconnect situations. The configuration in Figure 1a is usually the most problematic method for power stability. Any transition currents convert directly to noise on the analog power. This is due to interconnect impedance and the impedance of the package and bond wire. A somewhat better layout is represented by Figure 1b. This arrangement eliminates the internal interconnect impedance as part of the analog circuit's power-supply connection.Independent Connections Are BestThe optimal circuit is shown in Figure 1c. It provides no direct path for noise due to digital transition switching on the analog circuit power. Consider independent connections for any analog circuits that generate large current transients.Isolated power supplies are preferred for analog circuits. Yet even separated power supplies become somewhat noisy due to internal coupling. Consequently, some noise will still be present on all nodes, but the effects due to V = L(di/dt) will have been minimized.The RF nature of system noise indicates that the interconnect impedance and its filter capacitors need to be taken into account. External power filter capacitors will have a maximum frequency at which they function as a filter. High-frequency models for any capacitor include some series inductance. Capacitors exhibit self-resonance at higher frequencies. At these levels, the series inductance, which is internal to the capacitor, starts to dominate the impedance equation. Larger-value capacitors go through self-resonance at lower frequencies.Parallel filter capacitors of different values can provide more effective power filtering at higher frequencies. Placing the filter capacitors' resonance points in staggered locations will provide a flatter power-to-ground impedance. Also, to minimize inductance of the pc-board connection, external filters should be placed close to the IC.Fig. 2At high frequencies, package and bond-wireinductance reduces the effectiveness of anyexternal filter. This diagram shows a powernetwork that includes package/bond-wireimpedance and high-frequency models forexternal capacitors.At high frequencies, package and bond-wire inductance lessens the effectiveness of any external filter. Bond wires are typically 2 nH. In many cases, the package will increase the total inductance anywhere from 5 to 10 nH. Figure 2 (above) shows a network that includes package/bond-wire impedance and high-frequency models for external capacitors.Filter Capacitors NeededCapacitors on the die become necessary for high-frequency filtering. Internal capacitance doesn't have to be big. But it does have to be able to provide the filtering that the interconnect inductance won't allow to be placed externally. The presence of active circuits and interconnects means that there will already be some internal filtering between the power rails due to parasitic capacitance. Additional internal filters also can be used without increasing the size of the IC.As circuits are floorplanned into the IC, empty locations in the layout can be "filled" with filter capacitors. Stacking metal power and ground connections provides metal-plate capacitors. There are often large metal-only interconnect areas in an IC, and the layers underneath the metal can be used for internal power filtering. This method has been used to provide sizable internal filter capacitors without increasing the IC size.A combination of proper power-supply separation and external/internal filtering should give a stable, low-impedance, low-noise power and ground for analog circuits. Substrate areas will benefit from extensive tie-downs to ground, thereby providing less noise in these areas. In a similar fashion, n-well areas can use extensive tie-ups to the power supply. The prior article covered these topics in more detail.Internal circuits can have long interconnects used for signal routing between circuits. To diminish coupling, it's better to keep analog signal paths short. Digital and analog signals should be kept away from each other when possible. When it's necessary for these signals to be in close proximity, shielding should be implemented to reduce coupling.Fig. 3Digital and analog signals should be keptaway from each other if possible. Whenthese signals must be in close proximity,routing the digital lines under a shieldinglayer will reduce coupling (a). Shields canbe used to both isolate the listener andsuppress the talker (b).Shields limit noise coupling to signals within noisy environments (Fig. 3 above). They can be used both to isolate the listener and to suppress the talker. Therefore, the routing of digital signals near an analog circuit can be shielded as well. This minimizes the effects that noisy digital signals may have on analog circuits.To be most effective, shields of analog signals should be connected only at the noise-sensitive receiver. The intention is to keep the noise level low, as referenced to the susceptible device.Talker-listener separation is especially important in the I/O cells and in the package/bond-wire area at the perimeter of the IC. I/O cells develop large transient currents when driving external loads and become significant sources of noise. Lead-frame and bond-wire structures can have significant inductance and significant coupling to adjacent pins.When developing a strategy for pin placement, signal and control pins can usually be classified into several groups. Among them are sensitive analog signals, wide-swing analog signals, static/inactive digital controls, and clocks or active digital signals. Also, determine the necessary number of power and ground pins. As discussed in the section on power/ground stability, provide multiple parallel power and ground connections to reduce interconnect impedance. In addition, designate separate power and ground pins for analog and digital circuits, noise-sensitive analog circuits, and circuits that generate current transients. The goal is to keep transition noise away from any linear circuits.Once a total pin count is defined, pin placement for the chip perimeter can be selected. Some guidelines follow:Analog pins will have lower amounts of noise when widely separated from active digital pins. Putting the analog and digital circuits at opposite ends of the chip is a common strategy here.The highest-frequency digital pins are usually the greatest noise source and should be given widest separation from the analog sections.Analog pins can be isolated by the use of adjacent ground or "quiet" dc power pins.Static digital signals are low noise, which means they can be used for separation. This includes Chip Select or Chip Enable types of functions.Any high-frequency digital pins should be separated by static controls or power/ground pins. Doing so decreases cross-coupling effects between adjacent digital pins.These guidelines aid in defining the perimeter of the IC. Once the perimeter is established, the designer can then turn to the placement of circuits within the IC.As a general guideline, attempts should be made to avoid long interconnects on any analog signals. Any externally connected analog signals should have their internal circuits at close proximity to their I/O cell. With a careful selection for pinplacement, this area should not have any close-proximity digital drive I/O cells.Analog Cells Can Be Noisy TooSome analog cells can be noise generators as well. Therefore, they need to be examined on a case-specific basis. Be aware of transition switching, high voltage, or current transients. Also, these types of circuits shouldn't be placed near low-amplitude signals or high-gain/bandwidth analog circuits.Modern digital design includes HDL definition, synthesis, and a computer-controlled placement and routing system. Trying to invoke placement selection during that stage of design isn't frequently done. When in the floorplanning stage of the design, however, there's an additional noise-reduction technique available.Before routing, the digital system can be separated into two groups--static digital controls and dynamic, actively clocked, digital circuits. Static controls consist of items that are of a "set and forget" nature. Control registers that are downloaded once at circuit startup are a good example. Active digital systems consist of all circuits that are continually clocked while the IC is functioning.Constantly clocked digital circuitry is the dynamic noise generator, not static devices. The static logic is quiet and can be used as a separation tool between the analog circuits and the dynamic logic. Placing the active digital farthest away from the analog circuits and using the static digital as a space buffer between them improves separation without increasing the die size.Fig. 4Floorplanning helps prevent mixed-signalIC noise problems. Placing the active digitalcircuits farthest away from the analogcircuits, and using the static digital as aspace buffer between them, improvesseparation without increasing the die size.The right side of the IC layout has the mostnoise sources, while the left side has thefewest.In Figure 4 (above), active digital circuits and digital I/O cells are grouped to one side of the chip. The right side of the layout has the most noise sources, while the left side has the fewest. Substrate noise is "soaked up" by a guard-bar structure between active and static digital circuits.Static digital circuits are used as a separation tool between the analog and active digital sections. Substrate noise is further limited through use of an additional guard bar, which is set at the center of the IC. The center guard bars include two sets: one referenced to the digital power/ground, and the other referenced to the analog power/ground.Within the analog part of the chip, any large-amplitude analog circuits are placed toward the digital side. Small-amplitude analog circuits are given the spot with the widest separation from the digital I/O area.Physical separation between some analog cells may also be needed. Any analog circuits with voltage/current transientsshould be considered for separation and isolation from more sensitive circuits.I/O drivers, due to their sizeable external loads, generate substantial surge currents when switching. These drivers should use the lowest drive strength necessary to meet clock-rate and load requirements. If the rise and fall time is much shorter than the design needs, there will be more noise due to the high-drive strength capability of the I/O cell. Plus, faster rise times lead to higher-frequency noise and greater problems with parasitic capacitance and inductance of interconnects.High-voltage-swing off-chip drivers can often be eliminated in favor of reduced-swing outputs, differential voltage outputs, or current-steering differential outputs. Moreover, output drivers that use a controlled-voltage rise time will produce lower bandwidth noise and smaller current transients.In the final analysis, addressing the noise problem as part of the design process enables the designer to create functionalsilicon with less need for redesign. Most noise problems are not seen in simulations. Engineers need to be aware of this and make an effort to examine their circuits as both a potential "listener" or possible "talker." Doing so reduces noise issues.Floorplanning, I/O selection, and pin locations can all affect noise and coupling between circuits. Most noise-reduction strategies do not cause die-size increases if carefully done. Build as much noise immunity into the system as possible. Noise suppression, shielding, guard rings, internal/external filtering, talker-listener separation, and power/ground/substrate stability will all help improve performance.Trying to deal with noise problems after design and fabrication frequently leads to a set of redesign cycles--suppressing the greatest noise source, refabricating the IC, and then discovering the next biggest source of noise in the IC. Hopefully, this can be avoided.。

ic版图设计面试知识

IC版图设计面试知识本文将为大家介绍IC版图设计面试中常见的知识点，包括布局与布线、时序与时钟、功耗与噪声等方面的内容。

通过对这些知识点的了解，可以帮助大家在IC版图设计面试中获得更好的表现。

一、布局与布线1. 布局布局是IC设计的第一步，它决定了各个功能模块在芯片上的位置和相互之间的布局关系。

在IC版图设计面试中，常见的布局问题包括：•功能模块的划分和组织方式•布局规则的遵守（如间距、阻抗匹配等）•对电源和地线的布局2. 布线布线是将各个功能模块之间的信号线连接起来的过程。

在IC版图设计面试中，常见的布线问题包括：•信号线的走向和路径规划•时钟线的布线•路由规则的遵守（如最小线宽、最小间距等）二、时序与时钟1. 时序时序是指IC芯片中各个时钟和数据信号之间的时间关系。

在IC版图设计面试中，常见的时序问题包括：•各个时钟域之间的同步问题•时序约束的制定和满足•时序的正确性验证方法2. 时钟时钟是IC芯片中起到供给同步时序的信号源。

在IC版图设计面试中，常见的时钟问题包括：•时钟树设计与布线•时钟偏移和时钟抖动的控制•时钟功耗和噪声的优化三、功耗与噪声1. 功耗功耗是IC芯片在工作过程中所消耗的电能。

在IC版图设计面试中，常见的功耗问题包括：•功耗优化的方法和策略•功耗的估算和计算•功耗的控制和管理2. 噪声噪声是IC芯片中由于电信号传输和耦合引起的干扰信号。

在IC版图设计面试中，常见的噪声问题包括：•噪声源的定位和分析•噪声的模拟和仿真•噪声的抑制和消除结语本文对IC版图设计面试中常见的知识点进行了简要介绍，包括布局与布线、时序与时钟、功耗与噪声等方面的内容。

希望通过这些知识点的了解，可以帮助大家在IC版图设计面试中更好地展示自己的能力和水平。

集成电路版图设计基础第8章：噪声问题

school of phye basics of ic layout design 6
利用常识解决噪声的方法
衬底可靠电位的连接：衬底可靠电位的连接： a. 尽量把衬底与电源的接触穿孔（substrate 尽量把衬底与电源的接触穿孔接触穿孔（ contact）的位置和该位置的管子的衬底注入极 contact）的位置和该位置的管子的衬底注入极（substrate injector）的距离缩小，距离越近越 injector）的距离缩小距离缩小，距离越近越好，因为这种距离的大小对衬底电位偏差影响非常大。 b. 把衬底接触孔的数量增多，尽量多打孔，保证衬底衬底接触孔的数量增多，尽量多打孔，保证衬底与电源的接触电阻较小。
GND noise
100mV
GND
big fat wire
noise
0mV
school of phye
basics of ic layout design
5
利用常识解决噪声的方法
衬底噪声( 衬底噪声(substrate noise) noise)
产生原因：产生原因：源/漏-衬底pn结正偏导通，或者电源连线接点引入衬底pn结正偏导通结正偏导通，或者电源连线接点引入串绕，使得衬底电位衬底电位会产生抖动偏差抖动偏差。的串绕，使得衬底电位会产生抖动偏差。解决方法：解决方法： a. 轻掺杂的衬底，用保护环把敏感部分电路包围起来轻掺杂的衬底，用保护环保护环把敏感部分电路包围包围起来 b. 把gnd和衬底在片内连在一起，然后由一条线连到 gnd和衬底在片内连在一起，然后由一条线连到片外的全局地线，使得gnd和衬底的跳动一致跳动一致，也片外的全局地线，使得gnd和衬底的跳动一致，也可以消除衬底噪声场屏蔽作用：每个block外围一层金属，使每单元 c. 场屏蔽作用：每个block外围一层金属，使每单元模块同电势模块同电势，而且模块之间不相互影响同电势，而且模块之间不相互影响

集成电路设计中的噪声分析与降噪

集成电路设计中的噪声分析与降噪随着集成电路的发展和应用不断扩大，噪声问题在集成电路设计中变得越来越重要。

噪声是指在电路中发生的任何随机性质的电信号，这种信号可以来自于电源、器件本身、环境等多种因素，它会导致电路的性能降低，从而影响电路的可靠性和稳定性。

在集成电路设计中，对噪声的分析和控制显得尤为重要，因为它能够保证电路的正常运作，提高电路的可靠性和性能。

噪声的来源主要包括两个方面，一是器件本身的噪声，二是来自于外部环境和电源的噪声。

器件本身的噪声来源十分广泛，常见的有电阻、二极管、晶体管、场效应管等。

这些器件中的噪声可以是热噪声、1/f噪声、射频噪声等。

而来自于外部环境和电源的噪声包括电磁辐射、磁场、热噪声、电源波动等。

这些噪声会对电路的正常运作产生不同程度的影响，特别是对精度要求比较高的电路，这些噪声必须控制在一定的范围内才能保证电路稳定和性能良好。

在集成电路设计中，噪声分析是重要的一项工作。

噪声分析主要涉及噪声源生成的机理和噪声的传输以及电路的噪声计算和分析。

在进行噪声分析时，需要熟悉它的统计性质，例如噪声的频谱密度、均方根电压、功率谱密度等，这些参数能提供给设计人员在进行电路设计时一个重要的参考，同时，通过噪声分析，设计人员还可以了解到电路中不同器件噪声存在的情况，从而可以选择合适的器件进行设计，在指导电路设计选择参数和优化设计时设置正确的噪声限制。

除了噪声分析外，针对电路中噪声问题的解决主要有两种途径：降噪和抗噪声措施。

降噪是指通过改善电路的环境条件或掉电路本身的设计，减少噪声产生或者噪声通过电路的传输，以达到降低电路中噪声的目的。

在降噪的方法中，有下面几种常用的方式：（1）提高信号的信噪比。

信噪比是指从信号中提取出有用信号的强度和噪音强度之间的比值，提高信噪比能有效地降低噪声的干扰。

在电路设计中，可以通过增大信号幅度、减小噪声幅度和提高信号频率等多种方式来提高信噪比。

（2）优化电路布局结构。

IC设计和版图中噪声减小的方法以及floorplan注意事项2

Noise Reduction Is Crucial To Mixed-Signal ASIC Design Success (Part II)Floorplanning, I/O placement, pinout, and power-stability issues round out the noise-reduction design problem.by Jerry Twomey IBM MICROELECTRONICSLarge CMOS ASICs and system-on-a-chip designs often contain both analog and digital sections. Combining the two into a mixed-signal IC frequently leads to noise problems. This article, the second in a two-part series, deals with noise-reduction matters affecting the whole IC.As discussed in the first article, engineers should think about addressing noise issues as part of the design process to avoid such difficulties during chip debug ["Noise Reduction Is Crucial To Mixed-Signal ASIC Design Success (Part I)," electronic design, Oct. 30, p. 123]. Dealing with the trouble after the fact can be costly. Complicating the situation is the fact that Spice simulations often don't show many noise problems. Impedance of interconnects, adjacent device coupling, and substrate noise are usually not modeled accurately.Transition switching noise is an RF issue, with a very broad spectrum. At these frequencies, connection inductance and parasitic capacitance become significant factors.Noise coupling is often distributed, with multiple talkers and listeners. Most effective methods of noise reduction include suppression of talkers at the source and use of noise-immune listeners throughout the IC. For our purposes, "noise reduction" refers to both reducing noise sources and using circuits and layouts that make the system less sensitive to noise. Note that including noise immunity in a design doesn't mean larger chips. Done properly, the die area usually doesn't change.Noise-Reduction MethodsNoise-reduction methods can be categorized into four areas: providing low impedance and quiet connections for power, ground, and substrate; designing analog circuits that are less sensitive to noise; reducing or silencing any noise generators; and separating the talker-listeners using proximity separation, separation in frequency, or separation in time.The following is a summary of the previous article, which dealt with noise immunity of internal circuits.• Differential circuits and signals provide common-mode noise rejection and less sensitivity to power and ground noise.• Limiting circuit bandwidth helps to avoid noise amplification--using just enough bandwidth to get the job done. Wide-bandwidth circuits would amplify undesired system noise as well. Plus, RF filters on analog signals can cut down on parasitic coupling of noise.• Reducing the number of external analog signals minimizes opportunities for noise coupling. Using large-amplitude signals directly improves the signal-to-noise ratio.• Internally distributed power filtering placed in unused areas, under metal traces, and in similar locations can provide better power stability, especially at high frequencies.• Extensive use of grounded substrate contacts, n-well tie-ups, and guard rings (well beyond what design rules require for latch-up protection) will reduce substrate noise.• Signal separation and shielding helps to avoid noise coupling through parasitic capacitance. In addition, by using separated analog-digital routing and keeping talker-listener signals apart, noise concerns will improve.• The most significant source of noise in most mixed-signal ASICs comes from digital transition switching. Strategies to decrease digital noise generation include minimum drive-strength devices, low-noise logic types, differential output drivers, and limited slew-rate devices.• Some analog circuits produce noise due to transition switching. On/off current situations, current and voltage pulses, and any switched step voltages are the items to look for here. Removing these elements, or reducing their effects as a noise generator, will give better noise performance.Following these eight noise-immunity tips for an IC's internal circuits will go a long way toward creating a noise-robust system. Attention then turns to integrating these circuits onto an IC. This includes circuit placement, selection of I/O drivers, pin placements, interconnect issues, and power, ground, and substrate concerns.At high frequencies, the impedance associated with interconnect metal, bond wire, and the package's lead frame can become a significant factor in the stability of internal power/ground. For the digital section, maximizing the number of parallel power/ground pins to reduce impedance should be considered as a starting point.Separating the power/ground connections used for the analog sections from those used for the digital areas will improve the isolation of the power supplies. Analog cells that use large current transients (large di/dt) should be considered for independent power/ground interconnects. If possible, consider redesign of these circuits to a current-steering method to avoid current transients on the power supply.Fig. 1Separating the analog and digital power/groundconnections will improve isolation of the powersupplies. The configuration in (a) is usually themost problematic method for power stability. Asomewhat better layout is shown in (b). The circuitin (c) is the best because it provides no direct pathfor noise due to digital transition switching on theanalog circuit power.Figure 1 (above) illustrates the possible interconnect situations. The configuration in Figure 1a is usually the most problematic method for power stability. Any transition currents convert directly to noise on the analog power. This is due to interconnect impedance and the impedance of the package and bond wire. A somewhat better layout is represented by Figure 1b. This arrangement eliminates the internal interconnect impedance as part of the analog circuit's power-supply connection.Independent Connections Are BestThe optimal circuit is shown in Figure 1c. It provides no direct path for noise due to digital transition switching on the analog circuit power. Consider independent connections for any analog circuits that generate large current transients.Isolated power supplies are preferred for analog circuits. Yet even separated power supplies become somewhat noisy due to internal coupling. Consequently, some noise will still be present on all nodes, but the effects due to V = L(di/dt) will have been minimized.The RF nature of system noise indicates that the interconnect impedance and its filter capacitors need to be taken into account. External power filter capacitors will have a maximum frequency at which they function as a filter. High-frequency models for any capacitor include some series inductance. Capacitors exhibit self-resonance at higher frequencies. At these levels, the series inductance, which is internal to the capacitor, starts to dominate the impedance equation. Larger-value capacitors go through self-resonance at lower frequencies.Parallel filter capacitors of different values can provide more effective power filtering at higher frequencies. Placing the filter capacitors' resonance points in staggered locations will provide a flatter power-to-ground impedance. Also, to minimize inductance of the pc-board connection, external filters should be placed close to the IC.Fig. 2At high frequencies, package and bond-wireinductance reduces the effectiveness of anyexternal filter. This diagram shows a powernetwork that includes package/bond-wireimpedance and high-frequency models forexternal capacitors.At high frequencies, package and bond-wire inductance lessens the effectiveness of any external filter. Bond wires are typically 2 nH. In many cases, the package will increase the total inductance anywhere from 5 to 10 nH. Figure 2 (above) shows a network that includes package/bond-wire impedance and high-frequency models for external capacitors.Filter Capacitors NeededCapacitors on the die become necessary for high-frequency filtering. Internal capacitance doesn't have to be big. But it does have to be able to provide the filtering that the interconnect inductance won't allow to be placed externally. The presence of active circuits and interconnects means that there will already be some internal filtering between the power rails due to parasitic capacitance. Additional internal filters also can be used without increasing the size of the IC.As circuits are floorplanned into the IC, empty locations in the layout can be "filled" with filter capacitors. Stacking metal power and ground connections provides metal-plate capacitors. There are often large metal-only interconnect areas in an IC, and the layers underneath the metal can be used for internal power filtering. This method has been used to provide sizable internal filter capacitors without increasing the IC size.A combination of proper power-supply separation and external/internal filtering should give a stable, low-impedance, low-noise power and ground for analog circuits. Substrate areas will benefit from extensive tie-downs to ground, thereby providing less noise in these areas. In a similar fashion, n-well areas can use extensive tie-ups to the power supply. The prior article covered these topics in more detail.Internal circuits can have long interconnects used for signal routing between circuits. To diminish coupling, it's better to keep analog signal paths short. Digital and analog signals should be kept away from each other when possible. When it'snecessary for these signals to be in close proximity, shielding should be implemented to reduce coupling.Fig. 3Digital and analog signals should be keptaway from each other if possible. Whenthese signals must be in close proximity,routing the digital lines under a shieldinglayer will reduce coupling (a). Shields canbe used to both isolate the listener andsuppress the talker (b).Shields limit noise coupling to signals within noisy environments (Fig. 3 above). They can be used both to isolate the listener and to suppress the talker. Therefore, the routing of digital signals near an analog circuit can be shielded as well. This minimizes the effects that noisy digital signals may have on analog circuits.To be most effective, shields of analog signals should be connected only at the noise-sensitive receiver. The intention is to keep the noise level low, as referenced to the susceptible device.Talker-listener separation is especially important in the I/O cells and in the package/bond-wire area at the perimeter of the IC. I/O cells develop large transient currents when driving external loads and become significant sources of noise. Lead-frame and bond-wire structures can have significant inductance and significant coupling to adjacent pins.When developing a strategy for pin placement, signal and control pins can usually be classified into several groups. Among them are sensitive analog signals, wide-swing analog signals, static/inactive digital controls, and clocks or active digital signals. Also, determine the necessary number of power and ground pins. As discussed in the section on power/ground stability, provide multiple parallel power and ground connections to reduce interconnect impedance. In addition, designate separate power and ground pins for analog and digital circuits, noise-sensitive analog circuits, and circuits that generate current transients. The goal is to keep transition noise away from any linear circuits.Once a total pin count is defined, pin placement for the chip perimeter can be selected. Some guidelines follow:• Analog pins will have lower amounts of noise when widely separated from active digital pins. Putting the analog and digital circuits at opposite ends of the chip is a common strategy here.• The highest-frequency digital pins are usually the greatest noise source and should be given widest separation from the analog sections.• Analog pins can be isolated by the use of adjacent ground or "quiet" dc power pins.• Static digital signals are low noise, which means they can be used for separation. This includes Chip Select or Chip Enable types of functions.• Any high-frequency digital pins should be separated by static controls or power/ground pins. Doing so decreases cross-coupling effects between adjacent digital pins.These guidelines aid in defining the perimeter of the IC. Once the perimeter is established, the designer can then turn to the placement of circuits within the IC.As a general guideline, attempts should be made to avoid long interconnects on any analog signals. Any externally connected analog signals should have their internal circuits at close proximity to their I/O cell. With a careful selection for pin placement, this area should not have any close-proximity digital drive I/O cells.Analog Cells Can Be Noisy TooSome analog cells can be noise generators as well. Therefore, they need to be examined on a case-specific basis. Be aware of transition switching, high voltage, or current transients. Also, these types of circuits shouldn't be placed near low-amplitude signals or high-gain/bandwidth analog circuits.Modern digital design includes HDL definition, synthesis, and a computer-controlled placement and routing system. Trying to invoke placement selection during that stage of design isn't frequently done. When in the floorplanning stage of the design, however, there's an additional noise-reduction technique available.Before routing, the digital system can be separated into two groups--static digital controls and dynamic, actively clocked, digital circuits. Static controls consist of items that are of a "set and forget" nature. Control registers that are downloaded once at circuit startup are a good example. Active digital systems consist of all circuits that are continually clocked while the IC is functioning.Constantly clocked digital circuitry is the dynamic noise generator, not static devices. The static logic is quiet and can be used as a separation tool between the analog circuits and the dynamic logic. Placing the active digital farthest away from the analog circuits and using the static digital as a space buffer between them improves separation without increasing the die size.Fig. 4Floorplanning helps prevent mixed-signalIC noise problems. Placing the active digitalcircuits farthest away from the analogcircuits, and using the static digital as aspace buffer between them, improvesseparation without increasing the die size.The right side of the IC layout has the mostnoise sources, while the left side has thefewest.In Figure 4 (above), active digital circuits and digital I/O cells are grouped to one side of the chip. The right side of the layout has the most noise sources, while the left side has the fewest. Substrate noise is "soaked up" by a guard-bar structure between active and static digital circuits.Static digital circuits are used as a separation tool between the analog and active digital sections. Substrate noise is further limited through use of an additional guard bar, which is set at the center of the IC. The center guard bars include two sets: one referenced to the digital power/ground, and the other referenced to the analog power/ground.Within the analog part of the chip, any large-amplitude analog circuits are placed toward the digital side. Small-amplitude analog circuits are given the spot with the widest separation from the digital I/O area.Physical separation between some analog cells may also be needed. Any analog circuits with voltage/current transients should be considered for separation and isolation from more sensitive circuits.I/O drivers, due to their sizeable external loads, generate substantial surge currents when switching. These drivers should use the lowest drive strength necessary to meet clock-rate and load requirements. If the rise and fall time is much shorter than the design needs, there will be more noise due to the high-drive strength capability of the I/O cell. Plus, faster rise times lead to higher-frequency noise and greater problems with parasitic capacitance and inductance of interconnects.High-voltage-swing off-chip drivers can often be eliminated in favor of reduced-swing outputs, differential voltage outputs, or current-steering differential outputs. Moreover, output drivers that use a controlled-voltage rise time will produce lower bandwidth noise and smaller current transients.In the final analysis, addressing the noise problem as part of the design process enables the designer to create functionalsilicon with less need for redesign. Most noise problems are not seen in simulations. Engineers need to be aware of this and make an effort to examine their circuits as both a potential "listener" or possible "talker." Doing so reduces noise issues.Floorplanning, I/O selection, and pin locations can all affect noise and coupling between circuits. Most noise-reduction strategies do not cause die-size increases if carefully done. Build as much noise immunity into the system as possible. Noise suppression, shielding, guard rings, internal/external filtering, talker-listener separation, and power/ground/substrate stability will all help improve performance.Trying to deal with noise problems after design and fabrication frequently leads to a set of redesign cycles--suppressing the greatest noise source, refabricating the IC, and then discovering the next biggest source of noise in the IC. Hopefully, this can be avoided.。

版图的匹配和抗干扰设计

偏置
参考
抗干扰设计
• 加滤波电容
– 电源线上和版图空余地方可填加MOS电容进行电源滤波 – 对模拟电路中的偏置电压和参考电压加多晶电容进行滤波 MOS CAP
P-P CAP
• 刻蚀速率与刻蚀窗的大小有关，导致隔离大的多晶宽度小于隔离小的多晶宽度均与周围环境有关 • 同类型扩散区相邻则相互增强，异类型相邻则相互减弱
匹配设计
• 系统失配
– 梯度效应
• 压力、温度、氧化层厚度的梯度问题，元件间的差异取决于梯度和距离
匹配设计
• 系统失配例子 ——电阻
– 电阻设计值之为2：1 – 由于poly2刻蚀速度的偏差，假设其宽度偏差为0.1u，则会带来约2.4%的失配 – 接触孔和接头处的poly电阻，将会带来约1.2%的失配；对于小电阻，失配会变大 R=R□•(Leff)/(Weff) R□=996欧姆 Wp = 0.1u 5u 2u
• 随机失配可通过选择合适的元件值和尺寸来减小
– 系统失配：工艺偏差，接触孔电阻，扩散区相互影响，机械压力，温度梯度等
• 系统失配可通过版图设计技术来降低
匹配设计
• 随机统计波动 (Fluctuations)
– 周围波动(peripheral fluctuations)
• 发生在元件的边沿 • 失配随周长的增大而减小
Analog Power Digital Analog Digital Power
抗干扰设计
• 电容的屏蔽
电路中的高阻接点接上极板，以减小寄生和屏蔽干扰；电容下面用接地的阱来屏蔽衬底噪声此地应为“干净” 地！可独立接出，不与其他电路共享
CAP
抗干扰设计
• 敏感信号线的屏蔽

模拟版图面试基础知识

模拟版图面试基础知识导语模拟版图设计是电子设计自动化（EDA）领域中的重要组成部分。

在进行模拟版图设计工作时，掌握一些基础知识是非常重要的。

本文将介绍一些模拟版图设计的基础知识，帮助读者更好地理解和应用于实际工作中。

一、什么是模拟版图设计？模拟版图设计是指将模拟电路设计图转化为实际硅片上的版图布局的过程。

在模拟版图设计中，需要考虑布局的物理特性，如电源线的位置、晶体管的尺寸和排列等。

通过合理的版图设计，可以提高模拟电路的性能和可靠性。

二、模拟版图设计的基本原则1.信号流向一致性：在设计模拟版图时，应保持信号的流向一致，以确保电路的正常工作。

信号的流向应符合电路的逻辑功能。

2.电源线布局：在模拟版图设计中，电源线的布局非常重要。

应尽量减小电源线的阻抗，降低电源线的噪声，并减小电源线对其他信号的干扰。

3.晶体管布局与尺寸：晶体管的布局和尺寸对电路的性能影响很大。

应合理选择晶体管的排列方式和尺寸，以提高电路的性能和可靠性。

4.引脚布局：引脚的布局应考虑到电路的输入输出关系和信号传输的最短路径。

合理的引脚布局可以减小信号的传输延迟和功耗。

5.管脚电感和电容：在模拟版图设计中，应注意管脚的电感和电容，避免对电路的工作产生不利影响。

三、模拟版图设计中常用的工具在进行模拟版图设计时，通常会用到一些专业的工具来辅助设计，如下所示：- Layout XL：这是一款常用的模拟版图设计工具，提供了丰富的布局和布线功能，可以帮助设计师高效完成版图设计任务。

- Cadence Virtuoso：这是一款功能强大的版图设计工具，支持多种设计规则和布局约束，可以满足不同项目的需求。

- Mentor Graphics：这是另一款常用的模拟版图设计工具，也提供了丰富的功能和易于使用的界面，被广泛应用于模拟电路设计领域。

四、模拟版图设计的挑战与发展趋势虽然模拟版图设计在电子设计中起着重要的作用，但也面临着一些挑战。

其中，主要包括以下方面： 1. 面积与功耗的平衡：在模拟版图设计中，需要在面积和功耗之间取得平衡。

集成电路版图设计

集成电路版图设计
集成电路版图设计是指将电子元器件（如晶体管、电阻、电容等）根据电路图的要求进行布局和连线的过程，实现电路功能并将其制作成一张版图以供电路的制造和生产。

集成电路版图设计主要包括以下几个步骤：
1. 电路分析：根据电路的功能及要求，进行电路分析，确定电路的基本结构和模块。

2. 元件选择：根据电路的功能和性能要求，选择合适的元件进行布局。

不同的元件具有不同的特性，如低噪声、快速开关、高频率等，需根据实际要求进行选择。

3. 布局设计：根据电路的结构和模块，将元件进行合理的布局。

布局的目的是使得电路平衡，减少干扰和噪声，并提高电路的稳定性和可靠性。

4. 连线设计：根据电路的功能要求，将各个元件进行连线，形成完整的电路。

连线的设计需要合理安排电路信号的传输路径，避免信号干扰和交叉干扰。

5. 优化设计：对布局和连线进行优化，以提高电路的性能。

例如，优化连线的长度和宽度，减少信号延迟和功耗。

6. 输出版图：将优化后的电路设计转化成计算机可识别的格式，并输出成版图文件。

版图文件可以用于电路的制造和生产。

集成电路版图设计的目的是在满足电路功能要求的前提下，使电路布局和连线达到最佳性能。

对于大规模集成电路（VLSI）设计，还需要考虑功耗、热量和信号完整性等因素，以实现高集成度和高性能的电路设计。

随着技术的不断发展，集成电路版图设计也在不断演进，从传统的手工设计发展到计算机辅助设计（CAD）和自动化设计（EDA），大大提高了设计效率和准确性。

集成电路设计的低噪声与高精度

集成电路设计的低噪声与高精度集成电路（IC）设计是一个复杂且精细的过程，尤其是在低噪声和高精度方面。

随着科技的不断发展，集成电路在各个领域中的应用越来越广泛，如通信、医疗、航空航天等。

这些应用对集成电路的性能提出了更高的要求。

本文将详细探讨集成电路设计的低噪声与高精度。

1. 低噪声设计在集成电路设计中，低噪声是一个重要的性能指标。

噪声会影响电路的稳定性和准确性，从而影响整个系统的性能。

为了实现低噪声设计，需要从以下几个方面入手：1.1. 选用低噪声元件在设计过程中，应选用具有较低噪声特性的元件。

例如，在模拟电路中，选用低噪声放大器和运算放大器；在数字电路中，选用低功耗、低噪声的逻辑器件。

1.2. 优化电路布局电路布局对噪声有重要影响。

合理的布局可以降低电路间的干扰，从而降低噪声。

在布局时，应注意以下几点：•尽量缩短信号路径，减少信号传输过程中的噪声积累；•电源和地线应尽量粗，以降低电阻和电感；•数字和模拟电路应分开布局，以减小相互干扰；•高速信号和低速信号应分开布局，避免相互干扰。

1.3. 滤波设计滤波是降低噪声的有效手段。

在设计过程中，应根据系统的实际需求，采用合适的滤波器。

例如，在模拟电路中，可采用低通、高通、带通、带阻等滤波器；在数字电路中，可采用数字滤波器。

1.4. 降噪技术除了上述方法外，还可以采用一些降噪技术，如差分放大、噪声抵消、电容耦合等。

这些技术可以有效地降低噪声，提高电路的性能。

2. 高精度设计高精度是集成电路设计的另一个重要指标。

高精度设计可以保证电路在特定条件下具有较高的性能稳定性。

为实现高精度设计，需关注以下几个方面：2.1. 选用高精度元件在设计过程中，应选用高精度、低失真的元件。

这类元件具有较好的线性度和稳定性，有利于提高电路的精度。

2.2. 温度补偿温度对集成电路的性能有很大影响。

在设计时，应考虑温度补偿措施，以减小温度变化对电路性能的影响。

例如，采用温度补偿电路、选用温度特性较好的元件等。

城市噪声地图绘制与噪声污染控制措施

城市噪声地图绘制与噪声污染控制措施噪声是城市生活中不可避免的问题，严重的噪声污染会对居民的身心健康产生负面影响。

因此，绘制城市噪声地图并采取相应的噪声污染控制措施是至关重要的。

本文将讨论城市噪声地图的绘制方法以及噪声污染控制措施。

一、城市噪声地图的绘制方法城市噪声地图是通过对城市中不同地点的噪声水平进行测量和分析而绘制出的一种地图。

绘制城市噪声地图的方法如下：1. 测量与数据收集：需要对城市中的多个点位进行噪声水平的测量。

可以使用专业的噪声测量仪器，比如噪声计，以获取准确的数据。

在测量过程中，应选择不同类型的地区，包括商业区、工业区、住宅区等，以获得全面的噪声数据。

2. 数据分析与处理：将测量得到的噪声数据进行分析和处理，通常采用专业的地理信息系统（GIS）软件。

该软件可以将噪声数据与地理坐标相结合，生成城市噪声地图。

通过对数据的处理，可以得到每个地点的噪声水平以及整个城市的噪声分布情况。

3. 地图绘制：根据数据分析的结果，绘制出城市噪声地图。

地图可以采用热力图的形式展示噪声水平，不同颜色代表不同的噪声水平，使其更加直观地反映城市中不同区域的噪声状况。

二、噪声污染控制措施绘制城市噪声地图是噪声污染控制的第一步，根据地图结果，可以采取以下措施来控制城市噪声污染：1. 分区规划：根据噪声地图的结果，将城市划分为不同的区域，如住宅区、商业区、工业区等。

在分区规划时，应合理安排不同功能区域的位置，尽量将噪声源与敏感区域相隔离，降低噪声对居民生活的影响。

2. 建筑设计与改善：在城市建筑设计中，应考虑噪声控制因素。

采用隔音材料、减震设计等技术手段，降低建筑物对外界噪声的传递。

对已建成的建筑物，可以通过改善窗户、门等部位的密封性能，减少噪声的进入。

3. 交通管理：交通噪声是城市中主要的噪声来源之一。

采取措施控制交通噪声对居民的干扰，如设置减速带、建立噪声屏障等，降低交通流量和车辆速度对噪声的贡献。

4. 绿化与景观规划：植被具有吸声的作用，因此，增加城市的绿化覆盖率可以有效降低噪声水平。

如何使用测绘技术绘制精确的环境噪声分布图

如何使用测绘技术绘制精确的环境噪声分布图测绘技术在现代社会中扮演着重要的角色，它不仅可以用于绘制精确的地图和三维模型，还可以应用于各个领域，例如测绘环境噪声分布图。

环境噪声是人们日常生活中经常遭受到的一种污染，它对人们的健康和社会安宁造成着严重影响。

因此，使用测绘技术绘制精确的环境噪声分布图是十分必要且具有重大意义的。

环境噪声是指来自于交通、工厂、建筑工地以及机械设备等源头的噪音。

环境噪声的高低和分布不仅与噪声源的类型和数量有关，还与环境的地理地貌以及建筑结构等因素有关。

为了绘制精确的环境噪声分布图，首先需要收集大量的噪声数据，然后进行处理和分析。

测绘技术可以提供帮助，使得数据的收集和处理更加准确和高效。

测绘技术的应用范围广泛，其中之一就是激光雷达技术。

激光雷达可以快速扫描并生成精确的三维模型，这对于环境噪声的测量和分析非常有用。

通过激光雷达扫描，可以获得噪声传播的具体路径和反射情况等信息，从而帮助我们理解噪声的传播规律。

此外，地理信息系统（GIS）也是测绘技术中不可或缺的一部分。

GIS可以将收集到的各类噪声数据进行整合和分析，并将结果可视化。

通过GIS技术，我们可以清晰地看到噪声在特定区域内的分布情况，了解不同地区的噪声水平并进行比较。

而这些精确的分析结果可以为环境保护和城市规划等决策提供数据支持。

在测绘技术的辅助下，我们可以通过以下步骤绘制精确的环境噪声分布图。

首先，我们需要选择合适的测量点位来收集噪声数据。

这些点位应该分布在不同的地理位置，包括不同的噪声源和噪声传播路径。

通过对这些点位进行系统的测量，可以获取到准确的噪声数据。

接下来，将收集到的噪声数据进行整理和分析。

这一步可以使用GIS技术来处理，例如将噪声数据与地理地貌等信息进行叠加。

通过对噪声数据的整理和分析，我们可以了解噪声在不同地区的分布情况，并找出可能的影响因素。

然后，通过绘图软件将分析结果可视化。

可视化的环境噪声分布图可以更好地展示噪声的分布特征和规律，同时也方便专业人士以及相关部门进行决策和规划。

模拟集成电路版图的匹配和抗干扰设计(精选)PPT文档共35页

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30、风俗可以造就法律，也可以废除法律。 ——塞·约翰逊
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27、只有把抱怨环境的心情，化为上进的力量，才是成功的保证。——罗曼·罗兰
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28、知之者不如好之者，好之者不如乐之者。——孔子
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29、勇猛、大胆和坚定的决心能够抵得上武器的精良。——达·芬奇
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模拟集成电路版图的匹配和抗干扰设
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26、我们像鹰一样，生来就是自由的，但是为了生存，我们不得不为自己编织一个笼子，然后把自己关在里面。 ——博莱索
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27、法律如果不讲道理，即使延续时间再长，也还是没有制约力的。— —爱·科克
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28、好法律是由坏风俗创造出来的。 ——马克罗维乌斯

低噪声放大器的版图设计

低噪声放⼤器的版图设计⽬录摘要 (1)Abstract (2)第⼀章绪论 (3)§1．1 微波集成电路的发展历史和发展背景 (3)§1．2 微波单⽚集成电路的发展概况 (3)§1．3 低噪声放⼤器的研究意义和发展现状 (4)第⼆章集成电路版图设计⽅法与技巧 (6)§2.1 引⾔ (6)§2.2 集成电路版图设计 (6)§2.2.1 软件介绍 (6)§2.2.2 版图设计过程 (7)§2.2.3 布局时注意事项 (8)§2.2.4 版图设计⽅法 (8)§2.2.5 版图设计规则 (8)第三章低噪声放⼤器版图设计 (10)§3.1 CMOS⼯艺中的原器件 (11)§3.1.1 CMOS⼯艺中的电阻 (11)§3.1.2 CMOS⼯艺中的电容 (11)§3.1.3 CMOS⼯艺中的电感 (12)§3.2 版图设计中的布局 (13)§3.2.1 版图布局 (13)§3.2.2 线宽分配 (13)§3.2.3 噪声处理 (13)§3.2.4 对称性设计 (14)§3.3 版图设计中的匹配 (15)§3.4 电路结构 (20)§3.5 版图的设计 (21)总结 (28)致谢 (29)参考⽂献 (30)摘要集成电路版图设计是⼀个⾮常新的领域，虽然掩膜设计已经有30多年的历史，但直到最近才成为⼀种职业。

集成电路版图设计是把设计思想转化为设计图纸的过程，包括数字电路和模拟电路设计。

本⽂针对模拟电路，论述了版图设计过程，验证⽅法，以及如何通过合理的布局规划，设计出⾼性能、低功耗、低成本、能实际可靠⼯作的芯⽚版图。

低噪声放⼤器在任何射频接收系统中都位于系统的前端，其对射频接收系统的接收灵敏度和噪声性能起着决定作⽤，⾼性能低噪声放⼤器的设计与研制的关键是研制具有低噪声⾼增益的有源元件。

模拟电路版图设计中的匹配艺术

模拟电路版图设计中的匹配艺术深圳中兴集成电路设计有限公司金善子1．引言生活中我们经常会遇到这样的事情：收听CD播放器的时候,左右耳脉里发出的声音经常不一样,甚至当有人打开窗户的瞬间或者打开室内空调的过程中，随着温度的变化，CD发出的声音也会随之发生变化，因此我们就不厌其烦地调来调去。

同样的情况也会发生在手机和接受机中。

我们希望无论是CD播放器还是其它音响,它们相搭档的器件反应完全一样。

也就是说，其中一个放大器的频率和幅值能完全符合并跟踪另一个运放的频率和幅值响应，达到这一目标的方法之一就是匹配。

实现匹配过程中，版图设计是一个非常重要的环节。

一个优秀的版图可以大大提升一个设计。

2．实现匹配的方法匹配基本规则当集成电路产业刚刚起步的时候，制造工业仍然相对落后。

即使你将两个需要匹配的器件放的很近，我们也仍然无法保证它们的一致性。

现在虽然随着制造工艺越来越精确，但是匹配问题的研究从来就没有停止过，相反地，匹配问题显得日益突出和重要。

使需要匹配的器件所处的光刻环境一样,称之为匹配。

匹配分为横向匹配、纵向匹配和中心匹配。

实现匹配有三个要点需要考虑：需要匹配的器件彼此靠近、注意周围器件、保持匹配器件方向一致。

遵守这3条基本原则，就可以很好的实现匹配了。

2．1根器件法(Root Device Method)有时侯我们会遇到两个或者两个以上的而且阻值不同的电阻需要匹配。

如下图1所示，如何将这5个阻值不同的电阻做成最优化的匹配呢？图2则给出了正确的答案，我们不妨分析一下：2K1K2K500250图1 阻值不同的电阻需要匹配如果要满足上面5个电阻的匹配，需要考虑以下步骤：（1）首先，尽可能把这些电阻靠近放置，这是基本的要求（2）其次，要使这些电阻保持同一个方向（3）采用根部件的最好方法是找出一个中间值，用1K的电阻作为值将电阻串联和并联起来。

这种方法节省了接触电阻的总数使其所占的比例减少，面积也相当，现在占主导地位的是电阻器件本身的薄层电阻。

Cadnece版图设计技巧总结

Cadnece版图设计技巧总结Cadence 版图设计技巧总结在集成电路设计领域，Cadence 版图设计是至关重要的环节。

它不仅关系到芯片的性能、功耗和可靠性，还直接影响到芯片的制造成本和生产周期。

对于版图设计师来说，掌握一些实用的技巧能够显著提高设计效率和质量。

接下来，就让我们一起深入探讨 Cadence 版图设计中的那些关键技巧。

一、布局规划良好的布局规划是成功版图设计的基础。

在开始设计之前，需要对整个芯片的功能模块进行合理划分，并确定它们之间的连接关系。

这有助于减少布线长度，降低寄生电容和电阻，从而提高芯片的性能。

首先，要考虑电源和地的分布。

电源和地网络应该尽可能地均匀分布，以减少电压降和噪声。

可以采用多层金属来构建电源和地的平面，以提供低阻抗的路径。

其次，对于高速信号线路，要尽量缩短其走线长度，并避免穿越其他信号密集区域。

同时，要注意信号之间的隔离，以防止串扰。

另外，在布局时还要预留足够的空间用于放置 ESD（静电放电）保护器件、测试结构和封装引脚等。

二、器件匹配在模拟和混合信号电路中，器件的匹配性对性能有着重要影响。

为了实现良好的匹配，需要遵循一些原则。

首先，将需要匹配的器件放置在相邻位置，并采用相同的方向。

这样可以减少由于工艺偏差引起的不匹配。

其次，对于对称的电路结构，要保持布局的对称性。

例如，差分放大器的两个晶体管应该具有相同的环境和布局。

此外，在布线时，要确保匹配器件的连线长度和宽度相同，并且走在相同的层次上。

三、布线策略布线是版图设计中的关键步骤之一。

合理的布线策略可以减少信号延迟、串扰和功耗。

对于电源线和地线，要使用较宽的金属线来降低电阻。

同时，要避免出现锐角和狭窄的通道，以防止电流集中和电迁移现象。

对于信号线，要根据信号的频率和特性选择合适的布线层次。

高频信号通常需要走在顶层金属层，以减少寄生电容。

在布线过程中，要注意控制走线的阻抗，以保证信号的完整性。

另外，要合理设置过孔的数量和位置。

使用CAD软件进行城市环境噪声分析和控制

使用CAD软件进行城市环境噪声分析和控制随着城市化的加速发展和人口的增长，城市环境噪声污染已成为一个严重的问题。

噪声会对人们的健康和生活质量产生负面影响，并对城市可持续发展带来挑战。

因此，有效地分析和控制城市环境噪声是一项紧迫而重要的任务。

CAD软件，作为一种功能强大的工具，可用于城市环境噪声分析和控制。

本文将介绍CAD软件在城市环境噪声方面的应用及其优势。

一、CAD软件在城市环境噪声分析中的应用1. 数字地图制作CAD软件可以通过导入相关的地理信息数据，绘制出城市的数字地图。

这些数字地图可以准确地展示城市的地理特征和建筑物分布，为噪声分析提供基础数据。

在数字地图的基础上，可以方便地进行噪声源的定位和噪声传播路径的模拟。

2. 建筑物噪声模拟CAD软件可以根据建筑物的几何信息，模拟建筑物对周围环境的噪声影响。

通过添加材料和声学参数，可以对建筑物反射、透射和吸声等特性进行准确的模拟。

这些模拟结果可以用于评估建筑物噪声源对城市环境噪声的贡献，并为建筑物设计和规划提供科学依据。

3. 噪声源分析与评估CAD软件可以将城市中的噪声源进行分析和评估。

通过测量噪声源的声音强度，并考虑噪声的传播规律和路径，可以对噪声源进行定位和分级评估。

这些结果可以帮助城市规划者识别噪声污染的主要来源，并采取相应的控制措施。

二、CAD软件在城市环境噪声控制中的应用1. 建筑物设计优化CAD软件可以帮助设计师进行建筑物设计的优化，以减少建筑物对周围环境的噪声影响。

通过改变建筑物的形状、材料和结构等参数，可以降低建筑物的噪声反射和传播能力。

此外，CAD软件还可以模拟不同噪声治理措施的效果，如降噪门窗、吸声材料的添加等，为设计师提供科学的指导。

2. 城市道路规划CAD软件可以模拟城市道路的噪声传播情况，通过改变道路的布局和设计，优化交通流量和噪声传播路径，减少噪声的影响范围。

例如，通过添加隔音屏障、降低车速限制和优化车流组织等措施，可以有效地降低道路噪声，改善周围居民的生活环境。