A Complete Overview of Data Bus: Connect the Dots!

mwcms on June 7, 2021

A computer is nothing far from a digital city. It is a construction of various devices that work together to function as a singular unit. Like cities, that have roadways for transportation, computers use pathways, like a data bus, to transmit information, or data from one component to the other. 

Early Days 

Back in the early days, components, such as the RAMs and CPUs, didn’t use to be inside a single IC board. You could find them in spate individual cabinets instead. The information traveled from one cabinet to another, with the help of wire bundles, that people otherwise call, a bus bar.  

This bus bar later developed the name, “bus”. You can find two main designs of a bus, it can either consist of one or multiple lanes. Each lane is a single wire connection, and the data travels differently according to the number of lanes. 

The Architecture of the Data Bus 

The data bus is Bi-directional, meaning that it can allow the flow of data in two directions. A parallel bus is one that uses multiple different lanes to transmit information. These lanes align parallel to each other, and before the information passes, it breaks down into smaller pieces and is distributed amongst each lane.

This works incredibly well for situations in which you have to transfer a memory address. The parallel bus is impractical in modern computers. This is because as the number of lanes increases, so do space requirements, which ultimately means that you will need to have a bigger circuit. 

Anything that contributes to increasing the size of a computer is, therefore, undesirable in the modern age of portability and compact computing devices. To keep circuits small, multiplexers became the important featured busses. 

What this does, is divide a 32-bit address into two halves and then transmit them into two clock cycles by a 16-bit bus. This was a revelation, that not only increased the processing speed of the computer but at the same time required much less space, keeping devices relatively small. 

Serial Bus 

Not all devices will look to multiple-lane solutions when transmitting data.  Some even have functions that send one bit at a time across a singular lane. A serial bus will only use one lane to transmit multiple data. 

Initially, serial data buses did not have a place in practical computing. They were slower than parallel buses, and you could only use them for long-distance communications. As time progressed, alongside technology, transmission speeds and signal integrity started to improve. 

When you combine that with the weakness of parallel buses being prone to electromagnetic interference, you can understand why serial data buses are the transmission mechanism of the future. 

The Computer Bus

The design of the data bus has seen plenty of changes over the years. What first was just a huge of bundle of wires and separate cabinets, are now small integrations and sophisticated connections between microprocessors and motherboards.  

As computer systems started to get smaller and smaller, faster and more efficient bus architectures began their implementation. The CPU was a first breakthrough away from the system bus that used the Northbridge, and the Southbridge for communication between components. 

This arrangement gave certain components priority over others. This arrangement made computing systems efficient and faster. 

To Conclude 

Data buses are essential to computing systems, just like how a good transport system is to cities. Their presence allows for a unified ecosystem in the computer, which functions as a single unit. As technology advances, the design and functionality of the data bus is set for an evolutionary course.  Contact us to help with this or any questions you have about your next project!

What Software and other Tools PCB Engineers Use?

mwcms on May 10, 2021

Electronic engineers must understand the layout and design of the electrical circuits. It can be a strenuous exercise task for an engineer to work without printed circuit boards (PCBs). This is where the need for PCB designing software and tools comes into play. 

These software and tools help an engineer to design a blueprint of the PCB. Moreover, an engineer can use the software to pull old designs from the PCB libraries, customize design procedures, and verify circuits’ schematic designs. 

Basics of PCB Layout and Design Process

The success of PCB prototyping and manufacturing is a result of an immaculate design process. 

The printed circuit board design and the layout process are vital as they allow the engineer to create an error-free prototype and a flawless manufacturing process. However, the type of software and tool used to accomplish the layout and design is vital to the entire exercise. 

Before getting down to the software and tools, let us have a clear picture of the basic process of PCB design

  • Creation of schematic design
  • Capturing of schematic design
  • Determining PCB template, fixed components, card dimensions and heat sinks
  • Deciding PCB stack layers
  • Determining line impedance
  • Component placement
  • Signals trace routing
  • Generating Gerber file

Software and Tools Engineers Use

Engineers use several software and tools to complete the above-mentioned process efficiently and precisely. 

Electronic Design Automation (ECAD) Tool

This one is a category of design tools used for the process of schematic design capture. These tools work simultaneously in the modular design flow to produce PCB’s design description. Some of the most popular tools that fall within the ECAD category are as follows. 

  • ORCAD

The PCB design engineers use this software to create an electronic schematic and blueprint of the circuit board. 

  • EAGLE

EAGLE is an acronym for “Easily Applicable Graphical Layout Editor.” This software is a solution-driven design program for printed circuit boards. EAGLE contains a PCB layout editor, schematic capture editor, Bill of Material Tools (BOM), and auto-router. 

  • PADS

PADS is a layout tool that contains advanced analysis, schematic designs, and, most notably, the feature to collaborate from ECAD to MCAD. 

5 Popular Designing Software and Tools Used by PCB Engineers

Although there is a wide range of PCB designing software and tools available in the market, here are the top five. 

  1. Altium Designer – it is famous for its feature to simulate your printed circuit board using the Altium PCB software. 
  2. PCB Artist – this software by Advanced Circuits is famous for its best shipping record and active consumer base. If you are looking for an intuitive solution for PCB designing, look no further. 
  3. SolidWorks PCB – this one has a robust design technology with ease-of-use. You will also get an on-demand bidirectional mixing feature along with the flawless collaboration of CAD and PCB designs. 
  4. Ultiboard – this PCB designing software by National Instruments allows you to leverage modular hardware and an expansive ecosystem. You can benefit from a quick prototyping atmosphere and save hours on the development phase. 
  5. DipTrace – if you are looking for a comprehensive design solution, smart manual routing, and shape-based auto-route, DipTrace is the answer. This software has a single environment that enables you to benefit from the direct conversion circuit to board feature and revise the schematic annotations in run-time. 

Tips and Considerations: Learn to Improve Your PCB Design Skills

mwcms on April 26, 2021

Are you a printed circuit board (PCB) engineer wondering how you can learn or improve your PCB design skill? Well, you are in the right place, as this post will give you a brief insight into tips and considerations that can help you polish your skills. 

Most engineers are good at PCB designs. However, they lack some basic professional and personal skills they must master. You must begin with the basics and learn to practice your PCB designing skills with consistency day-in and day-out. 

5 Tips to Improve Your PCB Design Skills

Here are five basic tips to improve your printed circuit board designing skills.

  1. Learning more about the Layers

In case you wish to master the skills of designing a multi-layered PCB, you must have a clear understanding of printed circuit board layers. You must learn to revise your basics and learn about the latest standards and trends to ensure that your PCB design meets all the industry and global standards. 

  1. Remembering the Design Rules

There are numerous design rules that every PCB design engineer must follow. Some of the most essential ones are as follows. 

  • Aim for noise reduction
  • Remember the EMI/EMC considerations
  • Remember the thermal integrity considerations, i.e., dissipation of heat because of the power circuits. 
  • Remember the power integrity considerations, i.e., power loss in its path
  • Learn to design for test and add test points at several stages of design. 
  • Follow the design for manufacturing ideology. Always consider track width, drill size, clearance, etc. 
  1. Learning to Use PCB Designing Software 

As designing technology has evolved, using PCB design software is common. In case you are not good at using software, you must polish your skills to draw components, schematics, and printed circuit board layouts. 

There are several PCB designing software solutions available in the market. However, you must pick a few that are common in your industry. If you are enthusiastic about learning more than one design software, then this will give you a competitive edge over other designers and engineers when searching for a new job. 

  1. 3-D Modeling

While you learn to design a printed circuit board on software, do not forget to add a 3-D modeling feature into it. This will allow you to see an almost real depiction of your PCB design before manufacturing it. 

Moreover, this will also allow you to detect any design errors and help save back-and-forth revisions with the PCB assemblers. This will translate into lower cost and time efficiency. 

  1. Learning to Review Thoroughly

So, you have learned the standards. You know the layers and know how to use software to create a 3D model of your printed circuit board. What is next? 

You must always learn to improve your attention to detail. This is very critical if you wish to get your PCB design right the first time. This will again save you from a lot of hassle in the future because the tiniest flaw in the design may result in several revisions and sometimes the overhauling of the entire printed circuit board design. 

Here, you can also learn about the basics of documentation and aesthetics. This will allow you not only to write how the components’ placement should be but also customize how the PCB design must feel and look. 

The documentation part will allow you to clearly label where each component and connector must go and how it must look on the printed circuit board

 The Take-Away

Learning all of the above skills will allow you to improve your PCB design skills as well as learn how to document the guidelines for the assemblers. The more elaborate you are in your design, the better the results.  At Nova, we are always updating and improving our skills. Reach out for a consultation today.

There’s more than one Reason to Make a Flawless Printed Circuit Board

mwcms on April 12, 2021

A printed circuit board (PCB) is a very critical part of our modern-day electronic equipment. Your basic printed circuit board usually consists of large active and passive components. These components have side-to-side connections with each other that you can see via traces on the board. 

You can actually create larger circuits using smaller printed circuit boards using small-sized components. However, you must ensure to make a flawless PCB to make them a perfect choice for any manufacturer of electronic components, equipment, and instruments. 

Let us dive right in and see how making a flawless printed circuit board can help. 

7 Reason to Create Flawless Printed Circuit Boards

Here are seven of the fundamental but essential reasons why you must create flawless PCBs. 

  1. Saves Time and Energy

While traditional circuit board connection methods can take longer to connect each component, the PCB takes less time to assemble a circuit. 

  1. Compact Size 

If you are designing a characteristically printed circuit board, it will include numerous electronic components.  Instead of using current-carrying wires, you use copper tracks to interconnecting the components on a PCB. This gives your PCB finesse, compact design, and lightweight. 

A perfect PCB design will offer you a simple platform to arrange sophisticated electronic components in an efficient manner. This compactness enables you to create complicated and bigger electronic circuits in smaller form factors. 

  1. Preventing Lose Connections and Short Circuits

Creating a flawlessly printed circuit board will allow you to use copper tracks. This means there will be no chances of any short circuits or loose connections. 

  1. Ease To Repair

In case your PCB incurs damage, you can easily run a diagnostic on it to check and replace the failed components. The properly designed printed circuit board has clear labels for each electronic component mentioning their polarities. 

This also allows you the convenience to install and/or repair the board and its components. 

  1. Reduced Electronic Noise

A printed circuit board produces less electronics noise. The reason is that the organization of the component is so precise that the electrical current’s path between them is as smaller as possible. This translates into low radiation as well as reduced pick up of any electromagnetic waves. 

This also ensures minimal crosstalk between any of the electronic components and their varied traces. This is actually a big concern in traditional circuit boards. The electronic noise usually releases in the form of radiation, heat, and flickering sounds. 

  1. Cost-Effectiveness and Reliability 

Printed Circuit Boards are very cheap to manufacture, especially during mass production. Moreover, they offer reliability to the performance of your circuits. 

  1. Fixed Components

One of the most important advantages of designing a flawless printed circuit board is that all the components are firmly fixed to the board. The manufacturers use solder flux, which ensures that the components do not move from their place irrespective of how much you move the board.

Conclusion

Manufacturing a printed circuit board will cost you money. Therefore, you must ensure that you design a flawless specimen instead of getting issues from the assemblers or clients. It would be wise to involve your printed circuit board assemblers’ team from the beginning. 

This will allow you to gain valuable insight into how you can start making an impeccable printed circuit board design. Moreover, the assemblers can also give you valuable information about the new practices, trends, and materials to make flawlessly printed circuit boards. The more knowledge you have, the better your printed circuit board will be. In case you are looking for international standards. You can check out the Institute of Printed Circuits (IPC), as they are the global entity setting standards for printed circuit board designing, manufacturing, and assembly. We are also available to consult with you on any of your PCB needs.

Steps and Process Learn to Safeguard Your PCB Design

mwcms on March 29, 2021

Your printed board circuit designs are your intellectual property. Therefore, you must do your best to safeguard it. Maintaining data security is an essential and critical element of all sectors, especially when it comes to proprietary and intellectual assets. 

As a PCB designer and manufacturer, you must consider deploying adequate security measures to safeguard your PCB design from theft. However, you must take precautionary measures from the day of prototyping all the way to the manufacturing processes. 

Steps to Secure Your PCB Design

Here are some of the most fundamental processes you can deploy to secure your printed circuit board design. 

  1. Protecting Your Formula

You must protect your sensitive data and maintain security by granting access to authorized personnel only. In simpler terms, you must treat your printed circuit boards as your business secrets. Someone else getting a hold of your PCB designs and diagrams means they have your recipe to copy, taking away your competitive edge. 

  1. Implement Right Protocols

Preventing theft of your PCB design will require you to deploy stringent and adequate data access protocols. Moreover, it would be best if you also integrated data monitoring software throughout your organization. 

  1. Keeping it In-House

While you can resolve the previous issue using the right networking infrastructure and security practices, there is another way to protect your PCB designs.  If possible, try your best to keep the prototyping and manufacturing of the printed circuit boards in-house. 

However, if you have to outsource, then always select a manufacturing partner after rigorous research and testing. Make sure that they have an excellent market rapport and have adequate security and safety measures in place to prevent any leaks through their ranks. 

  1. Using Additive Manufacturing Systems

If you have no other option but to send your printed circuit board design with an on-shore or off-shore PCB manufacturer, then an additive manufacturing system can help. This way, you can produce quick-turn prototypes and finish the PCB entirely in-house. 

Another advantage of doing so is it will cost you very cheap per board and also reduce your fabrication time in comparison to conventional prototyping processes. 

Additive manufacturing protocols represent continuous evolution and automation. Chances are they will one day integrate into a connected network of factories offering PCB manufacturing services. 

As this process becomes more ubiquitous and its effectiveness and capability increase, industries will start adopting it as a common practice. Using additive manufacturing processes, engineers and designers working on printed circuit boards will be able to share and use these systems directly. 

However, you can use additive manufacturing systems at present to improve your level of security. Not only will it safeguard your PCB design but also improve productivity due to the flexibility it offers. 

  1. Using Subtractive Process 

Although not as quick as the additive process, you can use subtractive processes to add multiple layers to your PCB design security. You can have each component made from different manufacturers, and then put them together in-house or use a different manufacturer to do it for you. 

However, this will take more time and energy and require several back-and-forth assembly testing and steps. Moreover, you may face more difficulty if the PCB design has a complex geometry. 

Conclusion

In the end, it would be best if you can keep your PCB designing, prototyping, and manufacturing operations in-house. This will be the best way to safeguard your PCB design. The more you avoid exposing your designs to third-parties and non-authorized personnel, the better are your chances to prevent any instances of your intellectual property being stolen or copied. We take safeguarding your PCB design seriously. Let us know how we can help you!

Everything You Need to Know about MFD Capacitor

mwcms on March 15, 2021

A MFD capacitor is an electrical component responsible for altering the current to a single or multiple windings within a single-phase induction motor operating on alternating current. The primary purpose of using a capacitor is to generate a magnetic field. 

You can get two different types of motor capacitors, which are start capacitors and run capacitors. A start capacitor is the only operation during the startup phase of the motor and then disconnects from the circuit. 

On the other hand, a run capacitor continuously works to adjust phase or current shift to a motor or machine’s winding. The goal is to optimize the efficiency, performance, and torque of the motor. You can find a motor capacitor in an air-conditioning unit, spa pump, large fans, powered gates, etc. 

What are MFD Capacitors

A huge variety of capacitors come with the markings of mFD or MFD mentioned after their capacitance value. You will be able to see it as an MFD, and you can also see it as µF, which stands for microfarad. 

So, the question arises, are mFD and µF one and the same thing? The simple answer is they belong to the same measurement scale, i.e., mFD stands for “milli-Farad,” whereas µF stands for “micro-Farad.” There are mostly old capacitors manufacturing companies that are using mFD instead of µF capacitors. 

The reason is that it was a common practice back in the days to mark the capacitors as mFD or MFD. The reason was most likely because the machines could not produce the µ symbol print on the motor’s casing. 

There is also a possibility that the manufacturer simply had their own reasons to keep their capacitors known as MFD capacitors. 

You can measure capacitor through MFD ratings. An MFD or micro-Farad is a technical terminology used to describe the level of capacity in a capacitor. Therefore, the higher the MFD ratings of a capacitor, the more electrical current your capacitor can store. 

A standard capacitor may have an MFD ranging from 5 to 80 MFD. In case you are looking for an MFD capacitor but could not find one, you can always get µF. They both work the same; the only difference is the unit used to mention the level of capacity  

Four MFD Capacitors Facts You Must Know 

Here are five facts about MFD capacitors you must familiarize yourself with. 

  • MFD capacitors can only store different charges. They cannot increase the voltage you are receiving. However, they can only boost the voltage within the circuit. You may see a higher voltage going through your capacitor compared to the actual line voltage, but that is because of the EMF. Back EMF is essentially a counter electromotive force created by the motor and not the capacitor. 
  • The higher the level of capacitance, the more current on the start winding. 
  • Always abide by the voltage rating on the capacitor as it indicates how much voltage your capacitor can handle. For example, if it says 370v, you can replace it with a higher capacity of 440v. However, if your capacitor is already a 440v, you cannot replace it with a lower capacitance of 370v. 
  • You can always test your capacitor while the unit is operational. You can simply gauge the amps of the start winding coming out of the capacitor. Simply multiply the amps by 2652 in case of 60 Hz power and 3183 if you are on 50 Hz power. Now divide the number you got by the voltage across the capacitor. 

Conclusion

Now that you know what MFD capacitor stands for, you will never feel confused by the rating stamps. Whether it is µF or MFD, you only have to convert the micro-Farad to milli-Farad and vice versa.  Reach out to us with any MFD questions or concerns for your next project.

A Comprehensive Look at Fiducial PCB and Why It Matters!

mwcms on March 1, 2021

Are you new to PCB manufacturing or designing and wonder what Fiducial PCB are and if they are indispensable in modern manufacturing techniques?  Well, in that case, you are in the right place. This post will offer a concise but comprehensive into the matter.

What are Fiducial Markers?

Fiducial PCBs are basically printed circuit boards with fiducial markers. So assuming that you already know about PCBs, let us understand what fiducial markers are.

A Fiducial marker is a round-shaped copper that identifies a reference point for assembly machines to pick and place. They can help machines understand the orientation of your PCB as well as surface mount components on it.

The packages on these components have tiny pitches, such as Ball Grid Arrays (BGAs), Quad Flat Package (QFP), and Quad Flat-No-Lead (QFN)

Types of Fiducial Markers

Fiducial markers come in two categories when it comes to printed circuit board designing.

·         Global Fiducial Marker – refers to copper reference point found at the edge of your printed circuit board. This fiducial marker allows the assembling machine to understand the orientation of your board in terms of X and Y Axis. You can also use the global fiducial marker to compensate for skews in case the PCB clamps.

·         Local Fiducial Marker – refers to copper markers placed at the external corner of your quad-packaged surface mounting component. Your assembly machines use a local fiducial marker to identify the footprint of your components precisely. This reduces the errors in fiducial placements, especially when you have large quad-packaged and fine-pitched components in your PCB designs.

Are Fiducial Markers Still Necessary

According to some, removing fiducial markers on smaller printed circuit boards can allow you to maximize the space for any signal traces. As the PCB designing and manufacturing technology advances, you can omit local fiducial markers under certain circumstances.

For example, on smaller PCBs, your modern-day assembly machines can easily place SMT components via identifiers set in place by global fiducial points. Moreover, if your printed circuit board has components with a larger diameter, it may be acceptable to omit the fiducial markers as modern-day machines can accurately place components without an identifier. These include any surface mount components that have a pitch of 1.0mm or larger.

If you are a PCB manufacturer with the latest in-house designing and manufacturing machinery, you can take out the fiducial markers. However, if you are going to outsource your designs and manufacturing, then you must consider the manufacturer’s machine’s capabilities.

If their assembly machines need fiducial markers to read the layout of your PCB and where to place the component, you will have to mention them.

Speaking about the global fiducial markers, no matter how advanced your PCB manufacturing machines are, you should never omit them from your PCB design,

Best Practices for Fiducial PCBs

Fiducial markers on your printed circuit boards will help you get the best out of your assembling machines. However, here are some essential tips for your consideration.

·         You always make a fiducial marker in circular shape via a non-drilled copper layer.

·         The Fiducial marker on your PCB must not have any solder mask.

·         Speaking about the optimization of the fiducial marker’s size, always keep it from 1 to 3 mm.

·         You must also maintain a clearance area exactly equal to the diameter of your marker.

·         For the local fiducial marker, you must place a minimum of 2 markers diagonally at your surface mount component’s external edge.

·         For global fiducial markers, you must place 3 markers at your board’s edge to achieve the best accuracy.  In case you do not have enough space, then use at least 1 marker.

·         Your PCB’s fiducial markers must maintain a minimum distance of 0.3 inches from the edge of the PCB.

Conclusion

In the end, you must always check if your soldering mask opening and fiducial PCB sizes are correct. Some manufacturers may modify your Fiducial PCBs size in case you forget to size them correctly. Therefore, discuss with the assemblers before your board goes for mass manufacturing.

What Is A Reference Designator And How Do We Use It In Assembly?

mwcms on February 15, 2021

Reference designators help label the location on your wiring harness to make sure it is straightforward on PCB’s assembly. 

A reference designator typically consists of a single or two alphabets followed by a numerical presentation. There is a convention of using Jack (J) and Plug (P) for assigning references for the electrical connectors of a board’s assembly. 

Irrespective of the gender of each connector contact, Jack or (J) is a more fixed connector pair, whereas plug or (P) is a lesser fixed of the two. 

Does Your Board Design Need Reference Designator?

Although for some board designers, a reference designator is somewhat of an afterthought. But, if you neglect it too often, this innocuous label will begin to cause continuous trouble during your PCB assembly process. 

Hence, your CAD software automatically applies reference generators to your PCB layout. Later on, it transfers them onto the Bill of Material (BoM) without special attention. 

The automation of this process makes it easier to overlook the significance of a reference designator. So, we are going to highlight why it is important for the completion of your PCB assembly. 

How to Use a Reference Designator?

In this section, we will discuss how you can use a reference designator in assembly. With this knowledge at your disposal, you can always ensure to design a PCB assembly that is understandable and clear before you indulge in the PCB fabrication process. 

It will also help you in avoiding delays and other related mishaps due to unclear or inadequate labeling. 

Reference designators are necessary for a range of different steps during your PCB assembly process. Most notably, you will include them in the “Centroid file.” This data allows the pick and place machine to match components on your bill of material (BoM) to the actual coordinates mentioned on the PCB. 

A reference designator also plays a vital role in the Automated Optical Inspection (AOI) and Visual Inspection process. It allows you to verify whether each component is correctly in place as it should be or not. 

These labels also enable easier communication with your production team in case they have any questions or concerns about the design. Thus, the reference designator is one of the most integral and essential parts of the PCB design process. 

Is a Reference Designator Necessary?

Many PCB manufacturers ask if reference designator is even necessary for their specific designs. It is the most commonly asked question from the manufacturers working on High-Density Interconnected (HDI) boards. 

In these boards, the assembly space is extremely narrow, making it almost impossible to print reference designators onto the silkscreen layer. You may hear this question at times from other manufacturers with concerns about the aesthetics of their PCB itself. 

In such cases, the recommendation is to create an assembly drawing and submit it along with PCB design files. It is an effective way of including accurate reference designators in your BoM and Centroid files while keeping the silkscreen layer clear. 

You can ask the quality assurance team to be vigilant and double-check the assembly drawing you submitted for verification purposes. 

Conclusion

As far as the reference designators are concerned, you may catch minor design errors at times during your initial verification states or even while you are in the quotation and negotiation stages with the vendor.

However, this is mainly a mismatch between the Centroid or BoM or a repeated reference designator for different components. The latter is a common issue observed in panelized board designs. 

Ensure your customer services and quality management teams are efficient at catching these minor errors before the design hits the production process. However, the most recommended way to avoid this confusion entirely is to develop and adapt consistency in your reference designator design. 

Nova Engineering is ready to help you with our expert team of PCB engineers. Contact us today!

PCB Finishes-Electroless Nickel Immersion Gold

mwcms on February 1, 2021

The perfect electronic device has to be light and small while offering the capability of maximum electronic functionality. The PCB industry has driven towards advanced packaging methods to meet this pre-requisite. 

It involves increasing the integrated circuits’ density on a PCB board as well as combining several functionalities into a single dense package. 

Electroless Nickel Immersion Gold (ENIG)

Electroless Nickel Immersion Gold is a twin layered metallic surface finish of 2 to 8 micro inch Au over 120 to 240 micro inches Nickel.

The Nickel here works as a barrier for the copper and provides a surface to which you can solder your components. The gold is responsible for protecting the nickel plating during storage time and offers low contact resistance, which is a requirement for thin gold deposits. 

ENIG is undoubtedly one of the most used surface finishes in the PCB industry. It is all due to the implementation and growth of RoHS regulations. 

Surface Finish Viable for Wire Bonding Process

While electrolytic nickel gold surface offers immaculate performance for gold wire bonding, it does suffer from three deficiencies. Each of these shortcomings causes a major roadblock for ENIG’s use as the leading surface finish application for circuit boards. Here are the three deficiencies.

  • The process is very expensive and usually requires a high gold thickness.
  • As you use higher gold thickness, your solder joint reliability may reduce drastically. It is because of the tin-gold inter-metallic formation. 
  • The requirement of electrical bussing for establishing connections to the feature amidst the plating process will limit the densities of features you wish to achieve. 

The limitations mentioned above also provide an opportunity for an Electroless process. These may include ENEG and ENEPIG that involves Electroless gold and Electroless palladium.

This surface finish has its own advantages, such as cost and packaging reliability. The cost especially becomes one of the most worrying aspects of the process. With a recent spike in gold price value, the price of this type of surface finish is becoming more difficult to control. 

However, the cost of palladium metal is comparatively far lower than gold. Hence, manufacturers now have the option to replace gold with palladium for a cost-effective yet identical quality process. 

ENIG is a commonly used surface finish that uses a nickel layer, which actually is a nickel-phosphorus alloy layer. This phosphorus content has two categories that are phosphorus nickel or high phosphorus nickel. The application of both is not the same.

There are certain advantages associated with Nickel, such as it is suitable or a lead-free soldering process. The surface it produces is flat, fine, and smooth. You can store it for longer periods considering the storage conditions are decent and not too harsh. 

Additionally, Nickel is suitable for binding with aluminum and suitable for thick panels that can withstand attacks of several environmental elements. 

Advantages and Disadvantages of ENIG

Here are some of the advantages and shortcomings of ENIG surface finishes. 

Benefits 

  • It produces flat surfaces
  • It offers completely lead-free surface finish for PCBs
  • It is good for Plated Through Holes (PTH)
  • It offers longer shelf life for the circuit boards

Drawback

  • This process is very costly due to the high gold prices in the market
  • The surface finish is non-reworkable
  • Black nickel and black-pad
  • The surface finish can cause damage to ET
  • The circuitry on the PCB may experience signal loss (RF)
  • The whole process of the ENIG surface finish is quite complicated

Nova Engineering is here to help you. Contact us today!

PCB Finishes- Immersion Tin

mwcms on January 4, 2021

PCB surface finishes is a dynamic, demanding, and ever-evolving domain. With all the immersion-based coatings available in the market, printed circuit board manufacturers have produced consistent quality circuit boards. 

Immersion coated PCB surface finish uses a chemical process that involves depositing a flat metal layer on copper traces. The coating’s flatness makes it an ideal choice of surface finish for boards with small components. 

Immersion Tin is the least expensive of all types of coatings. It is very economical; however, it does come with certain shortcomings. One of the main drawbacks of immersion Tin is, once you deposit the tin onto copper, it will begin to tarnish. This also means if you wish to avoid low quality solder joints, it is imperative to do your soldering activity within 30 days. 

In case you are expecting higher production volumes, it is not an issue. Additionally, if you are manufacturing large batches of printed circuit boards quickly, you can avoid the tarnishing phenomenon. 

However, in you are not producing high volumes, it is probably better for you to choose an alternative surface finish such as immersion silver. 

Immersion Tin as an Alternative

As the name explains, this surface finish uses a very thin metallic layer of tin over the copper layer of your circuit board. Immersion Tin is a lead-free alternative for PCB surface finish and is capable of producing consistent flat surfaces, which is cost-efficient as well as solders well. 

The appearance of the thin layer is typically white. Therefore, this type of immersion finish is also known as “white tin” in the industry. PCB manufacturers apply this coating on copper via an Electroless chemical bath. 

The immersion Tin PCB surface finish protects the copper from oxidation. This protection lasts the entire shelf-life of the printed circuit board, which is another benefit of immersion Tin finish. 

However, it does require extremely careful handling throughout the circuit board assembly process. Due to this process being prone to damage caused during handling, it is better to establish an entire process that can help minimize PCB handling errors and mishaps.

Another problematic aspect of using immersion Tin is the strong affinity copper and tin have for each other. It ends up allowing the two metals to diffuse into one another, which may result in the formation of small strands known as “tin whiskers.”

These tiny strands of diffused tin can cause shorts in the circuits and reduce your PCB’s solder joints quality. This can adversely impact the performance and shelf life of your printed circuit board. 

Advantages and Disadvantages of Immersion Tin

Like any other finishes, immersion Tin PCB surface finish has its own sets of benefits and shortcomings. Let us have a look at them. 

Pros

  • It is a lead-free surface finish
  • It is highly reliable and produces fine quality
  • It produces planar or flat surfaces
  • One of the most cost-effective PCB surface finishes available in the market
  • It is a top choice when it comes to “Press Fit Pin Insertion”
  • It is re-workable

Cons

  • It is not a viable solution for PTH
  • It uses Thiourea in the process, which is a known carcinogen 
  • It is not ideal for multiple re-flow and assembly processes 
  • Known for the formation of tin whiskers
  • It could cause damage to solder mask
  • The immersion coating can be easily damaged due to handling mishaps and errors 
  • It is difficult to measure the thickness of the surface finish 

Final Thoughts

Although immersion Tin is a good alternative for lead-free surface finish, you will require decent storage conditions for the circuit boards. Additionally, it is best not to store them for more than six months, or else you will start noticing the formation of tin whiskers. 

If you have any questions about what you’ve just read or anything else related to your PCB assembly, feel free to reach out to us today. We’re here to help!