1. DesignSpark PCB
一天工作坊
Introduction and welcoming. A Printed Circuit Board (PCB) is a device that connects the different circuit elements. There is an Institute for Interconnecting and Packaging Electronic Circuits (IPC) standard for every aspect of PCB design, manufacture and testing. The Generic Standard on Printed Board Design IPC-2221 is an accepted world standard. The purpose of this ODW is to provide all attendees with enough background and exposure to the various DesignSpark features in the process of PCB design.

2. 工作坊要求 所有计算机都必须安装了 DesignSpark PCB 的最新版本，下载网站 : www.designspark.com/pcb
所有计算机都必须安装了LT Spice IV:
所有计算机都必须安装了Gerber viewer:
PCB 设计软件的基本认识是需要的。我们的课程主要目的是着重设计技巧、良好的操作方法与工业制造考虑– 并非只单纯教导如何操作 DesignSpark PCB 。
如需更多信息与支持服务，请访问我们的网页：
工作坊主要是使用的设计文件有 mesh_example.sch , ODW.sch and ODW_fixed.sch
更多 Spice 资源 (模拟的部分)是使用 integrator.sch and differentiator.sch

3. DesignSpark – 一天工作坊 项目 主题 标题
活动内容 1
PCB 板设计与生产制造
PCB 完整的循环 – 从设计到生产制造影片
影片观赏 2
PCB 板结构
PCB 铜箔、丝印、防焊油墨、导孔、表面黏着设计、通孔、安装孔
Power Point 介绍 – 实际 PCB 板批注图片 3
PCB 板设计
良好的设计习惯
Power Point 介绍 4 模拟
LTspice 、SPICE 模型 、仿真 、绘图 、转译和分析
练习：展示/辅助 LTspice模拟 5
DesignSpark 介绍
DesignSpark 操作环境 / 设计技术 /模拟输出
练习：展示/辅助 DesignSpark & LTspice模拟 6
DesignSpark 工业用档案
Netlists / Gerber 档案
练习：完整的原理图和PCB 板布局 – 展示/辅助产生 Gerber档案 7
DesignSpark – 产生PCB 板档案
PCB 封装符号/ 布局
练习：完整的原理图 – 展示/辅助原理图转文件至 PCB ，零件的布局和布线 8
DesignSpark – 原理图建立
原理图符号 / 图表
练习：展示/辅助建立原理图 ( 用现存的零件库零件) 9
DesignSpark – 建立零件库
原理图符号 / 封装/ 零件建立精灵
练习：展示/辅助产生零件
The DesignSpark ODW activities are as listed in the table. We will be following a top-down approach where we will start with a video-clip summary of the PCB design and manufacturing process. We will then examine a PCB structure to familiarise ourselves with the different elements and their naming conventions. Following that we will look at good design practices on both schematic and PCB layouts. Although simulation is not a big part of the ODW, we will explore the Simulation Program for Integrated Circuits Emphasis (SPICE) output capability of Design Spark and analyse a few outputs waveforms. The next slide will graphically explain the remainder of the top-down design process items 6 to 9.

4. 一天工作坊 – 练习 项目 主题 标题 活动内容 工业制造用 绘图 PCB 板设计 原理图设计 零件建立 6 7 8 9 6
工业制造用 绘图
PCB 板设计
原理图设计
零件建立 6 7 8 9 项目 主题 标题
活动内容 6
DesignSpark 工业用档案
Netlists / Gerber 档案
练习：完整的原理图和PCB 板布局 – 展示/辅助产生Gerber档案 7
DesignSpark – 产生PCB 板档案
PCB 封装符号 / 布局
练习：完整的原理图 – 展示/辅助 原理图转文件至 PCB ，零件的布局和布线 8
DesignSpark – 原理图建立
原理图符号 / 图表
练习：展示/辅助建立原理图 ( 用现存的零件库零件) 9
DesignSpark – 建立零件库
原理图符号 / 封装 / 零件创建精灵
练习：展示/辅助零件建立
Item 6 – Using an existing schematic as well as its related PCB layout, we will start by generating Manufacturing Plots such as the industry standard Gerber format (named after Gerber Systems Corp founded by Heinz Joseph Gerber).
Item 7 – Next we will go one level down and create a PCB layout from an existing schematic diagram.
Item 8 – Then we will generate a schematic diagram from components existing in the standard DesignSpark library.
Item 9 – Finally and on the lowest level we will generate components which will include both its schematic Symbol as well as the PCB Footprint Symbol.

5. PCB板的制造

6. PCB 制造过程 铜箔层压版到表面 玻璃纤维 PCB 板层构造 CTRL+ Click 观看这个影片
The process of manufacturing the Printed Circuit Board laminate is normally handled by a subcontractor. The PCB CAD files (or Gerber files) are sent to the manufacturer by . The process starts with bare laminate material which comprise woven glass reinforced epoxy resin with copper on both sides . The holes are drilled and chemically coated to improve the electroplating process. The laminate is placed in a copper plating bath and all the holes are electroplated which will connect pads on both sides of the board. The laminate is then coated with UV-sensitive photo-resist, after which the tracks are imaged onto each side using the photo-plots and exposure to UV light. The laminates are put in acid to etch away the unrequired copper therefore forming the track pattern . The bare copper PCB with tracks and pads is cleaned and ready for the solder masking and tinning. The bare copper is then solder masked which is normally a green or red colour by means of either silk-screening, photo-imaging or dry film. The exposed pads is then tinned or plated with solder, silver or gold. The bumps in the solder are made flat by hot air which is called hot-air-levelling. The white painted component identification and any board lettering and annotations are finally added by a silkscreen process.
As an introduction to the PCB design cycle from design to production the next video-clip will assist in the viewers obtaining the bigger picture. <<Ctrl & click on link>>
CTRL+ Click 观看这个影片

7. PCB板的结构

8. PCB板的结构
The main parts of a PCB can be seen in the annotated picture. The mounting holes are plated through but isolated from the circuitry. The Pads are the copper surface that the components will be soldered to and is either surface mount or Through-hole. The solder mask is a thin polymer coating on the board which surrounds the pads to help prevent solder from bridging between the pins. The size of track to be used depends on the electrical requirements of the design, the routing space and clearance available, and also personal preference (note - the bigger the track width the better). Vias and through-holes are holes in the laminate with electroplated copper on the surface forming a bridge between two (or more) conducting layers. Line art and text indicating board identification, component designation & outline, pin identification, test points, etc. are printed onto the outer surfaces of a PCB by silkscreen which is also called screen printing.

9. 重要尺寸大小
1 inch
25.4mm
1 inch = 25.4mm
1 “thou” 等同于 1/1000th inch，所以也等于 mm (25.4/1000)
1 inch = 25.4mm
A “thou” is 1/1000th of an inch (0.0254mm) and is universally used and recognised in PCB designs.
A “mil” (or “mils”) while 1 “mil” is the same as 1 thou, and should NOT to be confused with the millimeter (mm).
As a general rule, use thou/mil for tracks, pads, spacing and grids, which are most basic “design and layout” requirements.
Only use mm for mechanical and manufacturing type requirements like hole sizes and board dimensions. Note: certain components are often dimensioned in mm or thou only, so you must be able to be comfortable working in both.
1 oz (=1.4mil) = 36um. Remember that the copper thickness normally 1 oz. (1 ounce = 28g)

10. 原理图设计 组成好的原理图有哪些要素? 相对的符号尺寸 零件参考 (e.g. U1) 零件数值 (e.g. 100uF)
零件功率或电压额定值
相对的字体和字型
线条尺寸 ( 与零件接脚的尺寸一致 )
放置输入/输出在各自一边或同一边
A4 布局、名称、数字、修正
提升电阻
去耦电容器
电路分割成逻辑/功能方块
良好的接地
A schematic is a presentation of the element-by-element relationship of all parts of a system. <<Discuss each point which will appear on separate mouse scroll/clicks>>. An example of a schematic will follow on next slide.

11. 原理图设计
组成好的原理图有哪些要素?
This is a simple schematic diagram showing a few of the points previously discussed. What can be seen is the: Relative Symbol Size, Reference (e.g. U1), Component Value (e.g. 4700uF), Component Power or Voltage Rating (e.g. Cap 35V / Res 0.5W), Relative Text Font, Line size consistent with component Pin size, Input on the left & Output on the right, A4 Drawing Layout, Name, Number, Revision, Circuit partitioned into logical/functional blocks, Ground.

12. PCB板的设计

13. PCB板的设计 更大的线路具有较低的电阻值、较低的电感值，更易于制造〈因此更便宜〉，且更容易去检查和再制造处理。
10/8 线路/间距 数值即代表线路宽度不可以小于 10 thou，而且线路〈或是焊盘 、任何铜线〉之间的间距不可以小于 8 thou。
基础型板的典型表示法为 10/10 和 8/8 。
当线路/间距的数值越低，生产制造商在进行调整和蚀刻的过程中就必须越谨慎，生产成本也越高。
好的设计习惯是尽可能地保持宽线路，只有在为了满足间距要求时，才会变更为窄的线路。
线路的宽度最终将由两个因素来决定：通过的电流、可容忍的最大温度〈线路放热就像电阻一样〉。
Some good tips on track layout are the following:

14. PCB板的设计 藉由设定零件和线路的网格，使它们的位置可以捕捉到固定的网格位置上。
一个100 thou的网格是基础通孔工作的标准，50 thou则适用于一般的线路工作。
如果有特别需求，也可以设定 25 thou，甚至更小的网格。
网格可帮助零件保持整齐、对称，使它看起来更专业。
DesignSpark 捕捉模式非常适合进行工作网格固定步幅的分割片段。
导孔通常用于连接位于不同层的电路点，它们通常比通孔还小 ( 一般直径约为 mm ) 。
盲孔是将PCB的最外层电路与邻近内层以电镀孔连接，看不到对面。
一个用非常少的铜箔围绕住的导孔，称为「无连接盘导孔」。
请注意切勿把导孔用防焊油墨去覆盖，这样可以方便电路除错的过程。
A few suggestions on working with grids and a few points on vias:

15. PCB板的设计 组成好的PCB板有哪些要素? 封装尺寸 零件轮廓 (丝印 ) 零件放置方式 ( 对称的/ 存取组件 ) 零件参考 注释和指引
安装孔
相关电流承载要求的线路/ 焊盘
斜角线路
如果有特殊要求的测试点
丝印上的接脚号码
布局划分
散热考虑
覆/铺铜
<<Discuss each point which will appear on separate mouse scroll/clicks>>. Example of a PCB layout will follow on next slide.

16. PCB板的设计 组成好的PCB板有哪些要素?
The simple through-hole layout is an example of a few of the points as previously discussed:
Footprint dimensions, Component outline (silkscreen), Component Placement (symmetrical / access to components), Component References, Annotations and Guidelines, Unique Identification of PCB, Mounting Holes, Track / Pad size relevant to current carrying requirements, Miter Tracks (good looks), Pin Numbers on Silkscreen, Layout Partitioning, Thermal Considerations, Copper Pour.

17. 模拟
SPICE (Simulation Program for Integrated Circuits Emphasis)是用来验证电路设计和预测 电路行为的电路仿真器。
Spice拥有标准零件的仿真和数码数据库（如NAND，NOR，触发器和其它数码门，运算放 大器等），使它成为一个广泛的模拟和数码应用。
In general SPICE allows for circuit analysis using: Non-linear DC analysis, Non-linear transient analysis, Linear AC Analysis, Noise analysis, Sensitivity analysis, Distortion analysis, Fourier analysis, Monte Carlo Analysis. Design Spark has built-in SPICE parameters that can be assigned to components so that a circuit elements could be output to a number of standard SPICE simulators such as LsSpice, LTspice, B2spice and TINA. As an example to show the Design Spark SPICE output capabilities, we will explore the results using LTspice. A number of components come standard with Design Spark in the component library “ltspice.cml” which is what we will use in our example.

18. 模拟 A I = B The loop equations are Loop 1,
10(I 1- I2) + 30(I1 – I3) – 10 = 0
Therefore 40I 1- 10I 2- 30I3 = 10
Loop 2,
10(I 2- I1) + 15I2 + 5(I2 – I3) = 0
Therefore -10I1 + 30I2 - 5I3 = 0
Loop 3,
30(I 3- I1) + 5(I3 – I2) + 30I3 = 0
Therefore -30I1 - 5I2 + 65I3 = 0
电流计算
Mesh current calculations form part of most first year network theory courses. The first loop I1 starts from the top of the 10ohms resistor, through the 30ohms resistor, then through the 10V supply voltage back to the starting point. The second loop I2 starts at the junction of the 10ohms, 5ohms and 30ohms resistors, after which it flows up through the 10ohms, then through the 15ohms and finally through the 5ohms stopping at the junction again. The third loop I3 starts at the grounded side of the 30ohms resistor flowing up through the 30ohms resistor, then turn direction right through the 5ohms resistor and finally through the 30ohms again stopping at the grounded side of the 30ohms resistor. The example matrix (AI=B) is for the three loop network which results in the following by solving for the current matrix I, i.e. I=inv(A)*B:
I1=475mA, I2=198mA and I3 = 235mA (Current through 10Ω = I1-I2 = 277mA, through 5Ω = I2-I3 = 37mA, through 30Ω = I1-I3 = 240mA)
We will now examine the results of the Design Spark output to LTspice. Open Design Spark and open the file “Mesh_example.sch” and output to LTspice as is shown in next slide. A I = B

19. 模拟
Select the Output menu and Spice Simulation Output as shown. <<Click Mouse>> Select LTspice and browse to where the program is installed. Select OK. <<Click Mouse>> The LTspice output selection screen allows for the different types of analysis as previously mentioned. We will be examining the plot outputs so simply select OK. This will open LTspice with a blank plot screen. In LTspice on the plot screen, right click and select Visible Traces to chose either individual current values or more than one by holding in the CTRL key while selecting. Compare the obtained simulated results with the expected values.

20. LTspice (extra)
The LTspice components can be viewed in the ltspice.cml library. When these components are placed in a schematic, their parameters need to be manually added. We will start by looking at the resistor and capacitor and provide the detail that will be required by Design Spark to output the SPICE parameters correctly. <<scroll/click>> Select the resistor component and place. <<scroll/click>> Double click on the component to get the component properties. SPICE parameters need to be added as shown. <<scroll/click>> Now add a non-polarised capacitor to the schematic. <<scroll/click>> Also add the standard capacitor parameters as shown. The polarised capacitor would obviously require exactly the same two fields.

21. LTspice (extra)
Next we will look at a device such as an Op-Amp. The properties that are added are to inform LTspice that an existing LTspice model must be used. In our example we use the LT1001 Precision Operational Amplifier (refer to datasheet). We do this by first adding an opamp component from the ltspice.cml library to the schematic. Double click on the component and add properties as shown. <<scroll/click>> The device is X and the SpiceSubcircuit is the LT There is more to do in Design Spark to inform LTspice regarding this component which will have to specify but we will discuss this when we select the SPICE Simulation Output.

22. LTspice (extra)
Defining a source signal is very important fro any circuit. The standard DC supply is fairly simple, but to define a Pulsating signal i.e. square wave and triangle needs some more attention. We start by adding a Power Supply component which is a simple DC supply. <<scroll/click>> Add the properties as shown to a voltage sourde V, and a Source voltage of +15V. The same process is followed to generate a negative voltage. <<scroll/click>> Shows a -15V DC supply. There are more properties to add when generating a square wave and is referred to as a Pulse in SPICE. <<scroll/click>> Shows the parameters for a 1Vp-p 10kHz signal (1/10kHz = 100us) with 50% duty cycle (50% x 100us = 50us). <<scroll/click>> shows the remaining two properties.

23. LTspice (extra)
If we wanted to generate a triangular waveform we would modify the Pulse square wave to make the rise time the same as the fall time (1/2 period) and make the width zero. The example is a triangular source with a period of 400Hz (1/400Hz = 2.5ms).

24. LTspice (extra)
Now that we know how to specify all the properties, we can generate our Differentiator circuit to which we apply a 400Hz triangular waveform. The differentiator output will therefore be a square wave representing the inverse (negative) of the slope of the triangular wave. Generate the schematic as shown and add the SPICE properties to the components. The 0V always needs to be present in the schematic. Therefore place the Ground component and change the Net to 0 by right clicking and selecting property and ammend. Having completed this we select Output <<scroll/click>>.

25. LTspice (extra)
Select the Spice Simulation Output <<scroll/click>>

26. LTspice (extra)
Ensure that the LTspice simulator format is selected and that the Program points to the correct exe file and select Ok. <<scroll/click>> We want to examine the transient and therefore select the appropriate tick box as well as the Extra SPICE box. Select the Extra SPICE Data tab. <<scroll/click>> The instruction should be added to read the model for the LTspice component LT1001 device (op-amp) being used. Select Ok which will open the SPICE screen with a blank plot screen.

27. Spice
Right click on the blank plot screen and select Visible Traces. Select both by holding in the Ctrl button and select OK. <<scroll/click>> In blue we see the input waveform while the green shows the inverted (negative) value of the differentiation (slope) of the triangle wave.

28. LTspice (extra)
For the next exercise we want to evaluate the output of a square wave being integrated. From the analytical theory we know that integrating a square wave results in a inverted Triangle wave. In other words, when the square wave is positive the slope of the triangular wave is negative and vice versa.

29. LTspice (extra)
The results of the simulation is shown.

30. LTspice (extra) Sine Source LT Components
To generate a Sine signal the properties that need to be supplied or added are as shown. On the right is a reminder to add the library instruction whenever a Linear Technologies existing component and therefore model will be used.

31. DesignSpark简介 原理图符号 零件 PCB符号(封装) .ssl (原理图符号库) .stf (原理图技术文件)
.cml (零件库)
PCB符号(封装)
.psl (PCB符号库)
.ptf (PCB技术文件)
Now that we have seen a typical Design Spark Schematic, it is time to quickly look at some of the main features before we attempt our first design. There are three parts to a component namely a Schematic Symbol, a PCB Symbol (footprint) and a Component which is a combination of the two. There are therefore three libraries containing the detail for each of these parts as shown. Technology files can be used to provide the technology data such as units, grids and styles when creating library symbols. Technology files provide a means of setting most of the important parameters when starting a new design or on first performing a translate operation from schematic to PCB. We want to take a look at the detail contained in the technology files, but first lets see how we accesses the Schematic symbol, PCB symbol and the Component in DesignSpark.

32. DesignSpark 简介 Each mouse scroll/click will show the following:
Schematic Symbol
PCB Symbol
Component showing Schematic and PCB symbols linked

33. 技术文件
PCB 设计技术文件
Technology files are where Design Spark general settings are stored. Everything related to the Schematic is stored in the Schematic Technology File (.stf) and similarly all PCB settings are stored in the PCB Technology File (.ptf). Matching Schematic and PCB technology files can be created to enable you to define your own Net classes and to enable them to be transferred from Schematic to PCB. They also provide a means of defining complete setups for particular design processes and include everything from display colours, screen and working grids, standard net names (optional), standard dimensions for all drawing parameters, like tracks, connections, component pads and text, Design Rule clearances, Board outlines Board layers used and even the standard setups for the optional range of auto-routers. <<scroll/click >> This shows the PCB Design Technology detail.

34. 技术文件
设定例子
Grids, Units and Coordinates are also stored in the relevant Technology file and can be accessed and changed in the Settings tab. Remember to save the Technology file each time you make changes in the event that you want to keep it for future use.

35. DesignSpark 制造文件
We will start at the top level by generating the Gerber files from an existing design. First open the file riaa amp.pcb. To output the Gerber files select Output and then Manufacturing plots or press Shift-P. <<scroll/click>> Select the Auto-Gen Plots <<scroll/click>> Select Gerber <<scroll/click>> Select OK.

36. 制造文件
This screen shows the different plot outputs as well as the formats for which we require Gerber. <<scroll/click>> Clicking on each layer on the left will show the relevant layer that will be output. <<scroll/click>> Under the Settings tab all the settings related to each layer can be viewed by selecting the layer on the left. <<scroll/click>> Remember to select the Board Outline as shown. <<scroll/click>> Selecting Run produces the plot files. A free viewer such as Viewmate can be used to look at the plots as will be seen in the next slide.

37. 制造文件
Open PentaLogix Viewmate and select File - Import – Gerber or press F2. Select all the files previously produced by keeping in Ctrl while selecting. Click on Import to open all files. Now we can select and de-select the different layers on the left by clicking on the tick boxes. These are files that are required by the PCB subcontractor for manufacturing.

38. DesignSpark 产生PCB档案
Moving down one level, we will now be translating a schematic to a PCB and route the layout. Open the schematic riaa amp.sch. Select Tools and Translate to PCB which will open the NEW PCB Wizard. Select Next and choose the default technology file and select Units mm with precision 4. Precision is used to set the number of decimal places reported for units. If we wanted to design a two layer PCB, we would select the following settings <<scroll/click>>.Remember not to cover the vias with solder mask. <<scroll/click>> We can now define the board dimensions. <<scroll/click>> It is good design practice to position all the components outside of the board area to allow the designer to first place the components with mechanical constraints followed by the bulky components like microcontrollers and FPGAs. <<scroll/click>>For this example we do not want to save or overwrite the existing PCB layout so de-select the Save the PCB design to the file check-box.

39. 产生PCB档案
The result is that the board as previously specified is shown with all the components placed on the outside of the board. The connections between the components are often referred to as the rubber bands or the rats nest. The components can now be selected and moved onto the board. After you are pleased with the component placement we are ready to route.

40. 产生PCB档案
Select the Route All Nets icon which will result in the pop-up as shown on the right. Remember to select Miter Track (meaning bevelling each of two points to be joined at a 45° angle) and select Route. Once you are please with the layout it can be saved and Gerber files can be generated as previously demonstrated.

41. DesignSpark 建立原理图
To create a schematic diagram select File – New which will produce the New Design box. Select Schematic Design and OK. <<scroll/click>> Normally schematics are drawn black on white so we start by changing the colour scheme. Select View - Colors

42. 建立原理图
The colour scheme can arbitrarily be chosen. As a guide, choosing the colours as shown produces an easy readable schematic as demonstrated in the next slide.

43. 建立原理图
Following this, we are next going to draw a schematic diagram using components in the existing libraries.

44. 建立原理图
Nets that represent similar sets of signals can be grouped by assigning the same Net Class to them. A Net Class contains a set of properties that the group of nets referring to it share. Note that every net must have a net class, whether it has its own or shares with a group of nets. When designing a Schematic you assign each net a Net Class name. When the Schematic is translated to the PCB, for each net the matching net class is found in the PCB technology file (matched by name) and, if found, the PCB net class properties are applied to that net. The Net Class in the PCB design contains track thicknesses and via styles that will be used once routing is started. We therefore need to generate Net Classes. <<scroll/click>> We start by generating three simple Net Classes by selecting Add under the Net Classes tab.

45. 建立原理图
We will draw the Power Amp Circuit and use it to explore some of the Design Spark Features. The components can be found in the following component libraries:
transistors.cml, discrete.cml, connector.cml and schema.cml. (Make sure students enable Library Manager (CTRL+M) > Folders Tab > select the line ‘C:\Users\Public\Documents\DesignSpark PCB\Library’ and tick the ‘Folder enabled tickbox)
You will see that the connections are shown with a cross. It is good practice to use the cross to indicate unconnected pins so we will switch off the Connected Pins as shown in the next slide.

46. 建立原理图
It is a good idea to have the Symbol Terminals switch on and the Connected Pins switch off in the View Colours. This ensures you only see the cross on unconnected pins. This makes it easier when adding connections to the schematic to see which pins are left to be connected. <<scroll/click>>

47. 建立原理图
Next we want to ensure that the line styles match those of the components to ensure that the schematic has a uniform line width. We access the Design Technology File and Add a Connections Style (Add Style) with a width of 10 thou and name it as Normal <<scroll/click>>. Now we can go back to the connection lines and right click to edit its property and change it to Style Normal. While holding in the Ctrl button multiple connections can be highlighted and changed at the same time. <<scroll/click>>. This schematic can now be translated to a PCB (Tools – Translate to PCB) and routed which is a good exercise to complete. Remember that the PCB environment will not know the Net Classes so you can either create them and save the PCB Technology file, or Design Spark will automatically create them and allocate normal track and vias to the Net Classes.

48. DesignSpark 建立零件库 Working area looks like Graph Paper
The Library manager is accessed from the main menu in File - Libraries or Ctrl-L or from the Toolbar icon (book) and is used to manage all libraries. We will start by creating our own Schematic symbol and PCB footprint and link them into a component. If we setup our grids as shown, the screen actually appears as graph paper. We do this by selecting Settings – Grids which we finally save in our own Technology File.
Working area looks like Graph Paper

49. 建立零件库
We start a new Schematic symbol by opening the Library Manager and selecting on the Schematic Symbols tab. We want to load our previous Grid settings which we do by selecting Tech Files and selecting our previously save Technology File. We select New Item which opens a the symbol editor.

50. 建立零件库
For this exercise we will draw a diode symbol. We use the schematic symbol toolbar on the left to draw. While drawing you can right-click the mouse and change both the line style to something defined in the Technology File or the Segment Mode e.g. Free-hand, Orthogonal, Right-Angle, Miter (45degree) or Fillet. While drawing the horizontal line, right-click and select Change Style. Type a style name Line 10 and change the Width at the bottom to 10 and select OK. Right-click at the end of the shape to select the Finish Here. When drawing the vertical line (diode cathode) right-click and select Change Style. Type style name Line 25 and type 25 and select OK. To draw the solid triangle shape, choose Add Shape Triangle and while drawing right-click and choose Filled Shape. Design Spark automatically places the Symbol Origin S. You can place the References by selecting Add Reference Origin and place the required references such as Reference Name, Component Name, Package Name, Symbol Name, Description and Value. It can all be included in the one Reference or added separately as individual references. To add the pads/pins to the component, select the Add Pad or click on the Add Pad icon on the left (or F4). Place a pad on the left (N1) and one on the right (N2). In the event that we would want to add Terminal Names we would have to move the N1 & N2 to locations suitable for adding text away from the symbol. Save the symbol in the required schematic symbol library. Next we will generate the PCB footprint symbol.

51. 建立零件库
Because most through-hole components have a standard spacing of 2.54mm, we set our Grid to this dimension. <<scroll/click>> Standard vero-board and proto-board dimensions are 2.54mm (100thou) to accommodate these components.

52. 建立零件库
Similar to the schematic symbol, the PCB footprint symbol is created through the Library Manager. The Library manager is accessed from the main menu in File - Libraries or Ctrl-L or from the Toolbar icon (book) and is used to manage all libraries. Select the PCB Symbol. Select Tech Files to load previously saved Technology Files with Units and Grid preferences before selecting New Item.

53. 建立零件库
2.1mm
3mm
We start by adding a though-hole pad from the Add Pad (F4) selection. After placing the pad, right click and select properties. <<scroll/click>> Change the pad to have the dimensions as show on the right. For hand-assembly it is always better to have a Rounded Rectangular pad shape to ensure sufficient pad to allow for solder flow. This pad can be saved as a new style by adding a name into the Style text box (indicated with the red arrow). You will be prompted to Add the new style in the design, which means that it will be saved as a Pad Style in the Technology File for future use. Save this style as Style 1 <<scroll/click>> Selecting these pad dimensions results in the shape with a 2.1mm x 3mm rectangular pad. An important design rule to always remember is the relation between the track and the pad, as shown in the following slide.

54. 建立零件库 线路宽度指南: 信号 10 thou (0.254mm) 电源 40 thou (1mm) 接地 40 thou (1mm)
线路(T)/焊盘(P)/通孔(D)的关系为
Although the track size is mainly prescribed by the current carrying requirement as well as the manufacturing constraints, as a guide it is always advisable to keep the track width as large as possible. Power traces carry the most current so we always want as much track as possible. This produces another problem where the track meets the pad. Half of the track length has to be smaller than the track width of the pad. Exceeding this will result in not only a appearance defect, but also a weak point on the PCB.

55. 建立零件库
Our 1N4007 diode device has a pin spacing of 500thou or 12.7mm. We therefore place the pads 12.7mm apart which is 5 grid positions (2.54 x 5). <<scroll/click>> We then select our rounded rectangular pads which we can either individually specify or select from your previously saved style (Style 1). We add any References by selecting Add Reference Origin. <<scroll/click>> With our final layout showing the Symbol Origin (S), pin numbers (1 & 2), the Pin Names (N1 & N2) and the Reference Origin (R). Before the diode body outline can be added, the working grid must first be changed to a finer 1.27mm (select settings, grids and change to 1.27mm). The outline must be added on the Top silk layer as shown in the following slide <<scroll/click>>

56. 建立零件库
For adding the body outline, while drawing right-click and chose Change Layer (or press L) and select Top Silk. The PCB footprint symbol can now be saved to the appropriate library. We now have a schematic symbol and a PCB footprint symbol which we can link to form a component.

57. 建立零件库
To create our new component we select the Library Manager icon / Ctrl-L or select File – Libraries. On the component tab we select New Item. <<scroll/tab>> The next screen allows us to link a schematic symbol to a PCB footprint symbol. Select the two symbols using the Find Symbol for both the Schematic and the PCB. Chose an appropriate Reference, Package and save the new component in a suitable library. <<scroll/click>> Link the Schematic, PCB and Component pin numbers and save. Terminal names can be added to the component under the Sch Symbol Terminal Name which will now be visible only if it was selected in the properties when the symbol was created. The component is now available in both Schematic and PCB environments.

58. 建立零件库
There is a Symbol Wizard capability in both the Schematic and PCB Library Manager to assist in generating components. Pre-defined symbols can be selected and by providing a few parameters, components can be created similar to the manual process as previously described. <<scroll/click>> The PCB footprint symbols contain standard packages and the wizard requires a few simple parameters as available on the component datasheet to create the footprint. Keeping the schematic, PCB and component as separate entities allows the user to link multiple schematic symbols to any footprint and saving this combination as different components.

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