Tag Archives: pc board assembly

smt-assembly

SMT Assembly and Thru-Hole/Chip Functionality

PC Board, pc board assembly, pcb assembly, PCB Design, , ,

Printed circuit boards are parts of various electronic devices, home appliances, and vehicles. The function of these green chips depends on their material and assembly technology. Each step of PCB assembly is important and needs careful processing considering essential features.
Two methods are popular in PCBA, including, MT and THT. Let’s study them in detail.

Through-Hole Technology (THT)

Traditional PCB has through whole technology, involving both automatic and manual processes. THT is PCB packaging technology that involves pins or leads, besides, you have to insert the chips in the PCB through holes, soldering from below. The technique gives it the name through-hole.
Through-hole technology was more in practice till 1980 and every PCB device had this technology. Then SMT emerged where chips are installed on the surface. However, some PCBs still need through-hole chips, like capacitors and resistors.
THT needs more drilling, however, the device with this technology has a durable bonding with the circuit board.
Let’s look at the important steps of THT.

Installation Of Components

Engineers place PCB components with their hands, however, it needs precision depending on the design.
PCB Inspection
PCB inspection is crucial because most devices need flawless PCBs to work well. Most of the through-hole process is manual, so you have to make sure that the assembly is without any mistakes.
Printed Circuit Board Soldering
Soldering of components is also important as you have to fix the components manually. This is the last part of assembly, and the manual work makes it more reliable than SMT.

Why Is THT Still In Use?

Though THT is an old PCBA technology, you still need it for certain reasons, such as:

  • Even a hobbyist can assemble a circuit board with THT by using a soldering iron. It involves less hassle because the holes are away from surface pads compared to SMT.
  • If you observe a hobbyist application of the THT circuit board, you will see the ICs with the 8 or 14-pin having centers up to 0.100”xp.300”. Sometimes even the DIP processors have such spacing between the holes that helps in manual soldering, making the PC Board assembly easier.
  • After assembly, the troubleshooting or revision reduces in THT because it does not involve bridges between the pins, be it single or multiple components.
  • THT has better professional assembly, especially when a project is at a prototype stage. You can apply the through holes in a prototype layout to assemble the board faster.
  • After evaluating the board function, you can swap in the SMT having the same value, revising the circuit board’s layout. The new layout has small footprints to be inspected before final production. Such techniques reduce the front cost of a project which can benefit a subcontractor.

Remember that small products demand more pricing from outside vendors as they prefer high-volume production for continuous machine work.

Benefits Of Through-Hole Technology

  • When it comes to PCB design revision, a through-hole technology doesn’t need to create an additional solder stencil. So, manufacturers can save a huge amount of money on a PCB design having 2 to 3 revisions before it is ready to use. Besides, you don’t have to arrange the equipment for the pick and place function.
  • The manual inspection of a small lot of printed circuit boards reduces the fixture expenses or any other cost regarding linked setups.
  • Soldering is also cheap in THT, such as the tin-lead solder. Besides the issue of HASL or hot air solder leveling does not occur in through-hole technology, unlike SMT where the HASL makes it hard to place the components having a precise pitch.
  • You can easily assess the mechanical faults, including twists, and warps, and can deal with them while redesigning without affecting the assembly as what happens in SMT. Issues like twist and warp are not as problematic in manual assembly as in SMT.
  • The hand assembly of a PCB helps fit hard components by changing the wrist angle. Whereas the automated assembly needs an extremely flat circuit board for proper functioning.
  • THT can help pinpoint mechanical faults before it gets hard to resolve them. Otherwise, the inspection becomes costly when it has to go into the hands of three persons, including you, the contract assembler, and the PCB Manufacturer.
  • The components for THT are easily accessible that keep the job going without interruption. Moreover, you don’t need a third-party assembly in the case of small production.
  • With THT, the project timeline is predictable and easy to manage with minimum issues without causing any production delays.
  • Even if you don’t want to prefer a through-hole assembly, you must consider it as a temporary solution at early stages like validation and development. So, it can benefit anyone, including a hobbyist, any established company, or a beginner in this industry.

Surface Mount Technology-Surface Mount Chip

Surface mount assembly and SMT is other popular PCB assembly technology. It is an advanced method involving automation. Besides, it is ideal for smart PCBs that today’s smart devices need.
As the name shows, PCB components are directly installed on its top surface, whereas the device having a surface mount technology is called SMD. You can say that traditional through-hole technology is being replaced by surface mount assembly.
However, through-hole technology is still in practice for big transformers or power semiconductors as their components are not compatible with SMT. Likewise, many other heavy electronic devices with heat sinks need through-hole PCBs.
Surface mount technology has more positive aspects than negative pros, so let’s discuss them in detail.

Positive Aspects Of Surface-Mount Technology

SMT Involves Minimal Surface: The component area, volume, and size in an SMT are 70% less than the component area in through-hole technology. Even the component area can become 90% less than its volume in a traditional PCB having a through-hole technology. Likewise, the overall weight of the PCB reduces, as the components’ weight reduces by 70 to 90%.
It Enhances The Signal Speed: a PCB assembled with SMT has a fast signal transmission due to a short circuit. The assembly density in such technology can go up to 5.5~20 solder joints in one square centimeter, like when there is paste on both sides of the PCB. Similarly, a PCB with SMT has a high impact and vibration resistance that helps create high-speed electronic devices.
Excellent Frequency: In SMT, the board has either no lead or it is very small which reduces its parameters, decreasing the interference in terms of RF. It means that the PCB gets high-frequency signals, and the device having it works faster.
Minimum Packaging Cost: when it comes to an SMT packaging price, you will see it much lower than THT. Since surface-mount technology involves effective production tools, the usage of packaging material reduces thus cutting down its cost. However, the decrease in the cost does not affect the quality of an SMT circuit board.
You don’t have to bend or cut the component leads in the SMT boards which reduce the assembly time, making production faster than THT. So, the production cost also reduces by 50% as the manufacturing process of SMT is quite simple.

Additional Info

In SMT, the solder paste is applied with a stencil printer that helps finish a raw board better and faster than a traditional method. In other words, you get fineness in an automated assembly.
The installation of the components becomes easier, as solder paste makes everything clear due to printing. Each SMT process is well-inspected that helps have accuracy.
In SMT, the process of reflow soldering also makes a circuit board highly durable. In reflow soldering, the technician places the circuit board under high temperature to melt and reshape the paste, making it permanent. You can use both reflow soldering and automation or can switch from one to another, depending on your needs.
The important thing is to design and assemble a PC Board considering all the dos and don’ts and have a flawless end product.

Some Negative Aspects Of SMT Assembly

Surface-mount technology is not full of benefits, instead, it has some drawbacks, such as:

  • It has less power
  • It is vulnerable to damage
  • SMT requires high-quality soldering because poor soldering can lead to leakage, tombstoning, bridging, and several other risks.
  • It involves delicate installation, resulting in dropped components.
  • Its inspection is hard, especially, the visual test as it has multiple types of solder joints.
  • The equipment cost is high.
  • It involves well-trained technicians that increase the learning expenses.
  • It needs consistent updates of assembly equipment due to fast development.

Final Thoughts

Printed circuit boards involve different assembly techniques, including a through-hole technology, and a surface-mount technology. The component area, volume, and size in an SMT are 70% less than the component area in through-hole technology.
When it comes to PCB design revision, a through-hole technology doesn’t need to create an additional solder stencil. So, manufacturers can save a huge amount of money on a PCB design having 2 to 3 revisions before it is ready to use.
Would like to know more about Surface Mount PCBs or PCB Assembly Services? Email us at sales@pnconline.com

Six Basic PCB Design Principles

Six Basic PCB Design Principles

PC Board, pc board assembly, pcb assembly, PCB Design, Printed Circuit Board, Printed Circuit board Fabrication, Uncategorized, , , , ,

Printed circuit boards are vital parts of smart devices and several equipments as they provide current or electrical signals to run them. You need different elements to construct a PCB, such as:

  • Schematic design
  • Database login
  • Electronic component configuration
  • Design preparation
  • Wiring
  • Block division
  • Testing

If any issue happens during a process, you have to go back to the previous process to correct it. The layout of PCB components is a complex thin as it determines a board\s appearance and neatness. Moreover, it also affects the function of the end product or device. We will discuss below the six basic PCB design principles in terms of its components and other factors.

1-Components Layout and Clearance

You have to place the components evenly on the board, leaving some space on the edges. The components around the edge should be 3mm away from PCB edges. In general, designers leave 5 to 10 mm space around the edges.

The components should be only on a board’s one side. There should be a separate pad for each lead pin.

Don’t cross up and down the components’ layout and keep a certain distance between the nearby components on the board. However, this distance should not be too small as it can hinder PCB maintenance.

Components should be installed at a low height and its lead should not be more than 5mm away from the PCB, as it can affect its quality to bear vibration.

Printed Circuit Board components that reside on a pad’s both ends must be a bit larger than their axial dimensions. The pads should be located where the coordinate grid intersects. The central distance of the pad has to be more than the board thickness to have a neat layout.

According to IEC or International Electrotechnical Commission, the standard spacing of the coordinate grid should be 2.54mm, whereas the axillary spacing should be 1.27mm.

However, these standards practically impact a few processes, including automatic drilling, computer automated design, components welding, and automatic assembly. But, such a grid spacing is not restricted in the case of manual drilling.

2-Defined Solder Mask

Solder mask expansion should be well-defined as it can cause issues if you over-define or under-define it. Tombstoning may happen if you don’t define the solder mask properly. Like, one side cools down faster than another side, affecting the board. So, by following the right parameters, you won’t have to revise your design.

The solder mask opening should be larger than the pad. In general, it expands 4 mils or 0.1mm. However, both can also have the same size, depending on the Printed Circuit board Fabrication.

3- Via Type& Routing Width

You must use the right via for routing as it won’t work if its diameter or ratio is not precise. The current won’t pass correctly due to fused vias. So, via styles should be considered while routing the entire PCB.

The routs should have enough width to carry the current that your device requires. You must have an impedance-controlled routing that needs various impedance profiles. You have to apply these profiles to routing widths to ensure a functional layout. Don’t have routing at an acute angle even if the signals have a low speed as acute angle hinders manufacturing. Like, an acute angle can increase the corrosion, leading to an open circuit.

Whereas it is vital to avoid the acute angle in the case of high-frequency circuits because it fully changes the track width at the corners and results in poor signals and discontinued impedance.

Six Basic PCB Design Principles
Six Basic PCB Design Principles

4-Components Installation

Different PC Board components are installed either vertically or horizontally. The horizontal components are parallel to the surface of the circuit board. Whereas in vertical installation, components are perpendicular to the PCB surface.

Vertical components allow you to have more quantity on a board’s surface. It is ideal for hearing aids, semiconductor radios, portable instruments, or devices that need a dense placement of components. For vertical installation, components have to be lightweight. Don’t install heavy components in a vertical direction as it can affect a PCB’s mechanical strength. Moreover, it causes vibration, and components can collapse, making a circuit less reliable.

On the other hand, the horizontal installation provides mechanical stability, and the circuit board also looks neat. It also helps lay down the printed wires because it enhances the elements’ span.

You can use any installation method, depending on your needs but make sure to arrange components evenly and the circuit should be anti-vibration.

5-Considering The PCB Layout Type

PCB layout has either a regular arrangement of components or is irregular. In an irregular format, the axis of the components are not aligned with each other, so it seems messy. However, it helps lay down the printed wires easily as there is no restriction of direction. Such a layout is ideal for high-frequency circuits and involves a vertical installation.

Whereas in a regular format, the component axis is aligned and either parallel or perpendicular to the sides of a PCB. It provides a neat board and makes certain processes easier, like PCB assembly, debugging, welding, maintenance, and production.

Moreover, a regular format is ideal for low-frequency circuits where the board has a few component types and its surface is loose. However, the number of components is high and such an arrangement also suits electronic instruments. But, due to the direction restrictions, such a PCB has a complex layout of wires, increasing the overall length of the wires.

6-Factors That Affect the PCB Layout

You also have to consider the factors that affect a PCB layout, like the direction of the signals, device position electromagnetic interference, thermal interference, mechanical strength, etc.

  • Generally, the direction of the signal flow is from left to right of which left is the input and right is the output. It is also from top to bottom of which the top is the input and the bottom is the output. Connectors which are in direct connection to the input and output should be close to the input and output connectors. Integrated circuits or transistors should be the core components. Whereas other components should be located according to their electrodes’ location. You should also consider the size, a number of pins, shape, and polarity of components.
  • You should adopt certain ways to prevent electromagnetic interference that occurs due to different external factors, like spatial electromagnetic ways, poor wiring, poor installation of components, etc. You can avoid these issues during the layout design. But, interference will happen if the PCB design is not right
  • You should shield the components that interfere with each other. High-frequency components should have small wiring. Similarly, the components of weak and strong currents should be separated. Wires with high potential should be at a great distance to avoid 50Hz interference. Likewise, the metal components should not be adjacent or they should be well-insulated to avoid a short circuit.
  • While designing a PCB, you must know which components are temperature sensitive and which are heat components. The heating components like resistors should be located near the shell or near vent holes to dissipate heat. Don’t place many heating components near each other. Also, use fans or radiators to prevent the rise in temperature beyond its limit.
  • Whereas the temperature-sensitive components should be away from the heat source. In general, integrated circuits, transistors, electrolytic capacitors, and thermal components are temperature sensitive. These components get affected due to the rise in temperature, especially in a circuit’s long-term operation.
  • The board should also be mechanically strong and its center of gravity should be stable. Don’t install heavy or heating components directly on the board, instead, they should be under the chassis to have a stable board. If the board size is above 200mm it will cause mechanical stress, so it should be strengthened with a mechanical frame.

Finally, many PCB design software uses the power layer to have a fast design process. You can connect more wires to ensure the current has a minimum impedance or voltage drop down, thus giving enough ground return paths.

FAQs

1.How To Layout A Printed Circuit Board?
You have to follow certain steps to create a PCB layout. Such as making the schematic drawings, developing a blank PCB layout, creating a PCB stack-up, schematic capture, defining design principles, defining DFM, linking to PCB, placement of components, inserting drill holes, and the route traces.

2.Is It Hard To Design A PCB?
It is not hard to design your PCB if the electrical schematic is right. Besides, following the design parameters also makes the design process easy.

3.Why Is My PCB Green?
The color of the solder mask determines the PCB color. So, if the solder mask is green, you say that PCB is green. The solder mask shields a copper circuit to avoid shorts circuit or soldering issues.

4.What Is The Purpose Of Following PCB Design Rules?
PCB design rules or principles help you to develop a system to automate the testing of design requirements. You get an interface between the physical and logical sides to create a circuit board. So, you can automate the DFM tests by following the rules to ensure that you can build a PCB.
Would like to know more about Design Principles or PC Board assembly? Write us at sales@pnconline.com

printed circuit board

Differences Between IC and a PC Board

PC Board, pc board assembly, pcb assembly, pcb assembly near me, pcb board assembly, Printed Circuit Board, printed circuit board assembly, , , , , ,

Before discussing the IC, you must know what PCB is. The PC Board or PCB has electronic components to help a device function. All digital and electronic devices have PCBs, like consumer products, smartphones, computers, laptops, tabs, etc. The purpose of the PCB is to eliminate assembly issues and have less wiring, enhancing automation and production.
The PCB has different types in terms of the number of layers. Like, it is either a single layer, double layer, four or six layers, or a multilayer circuit board. Now, we will discuss the difference between PCB and integrated circuits.

What Is IC Or Integrated Circuit Board?

The integration of chips makes an integrated circuit, like chips used in a CPU and motherboard are ICs or integrated circuits. Initially, IC was called an integrated block. You will see the IC soldered on a printed circuit board. In other words, a printed circuit board carries the integrated circuit.
The purpose of the integrated circuit or IC is to integrate an ordinary circuit into a chip. So, if the IC gets damaged, the chip won’t work. But, if the PCB gets damaged, you can replace the components.

Printed Circuit Board and Its Components

PCB has different types, however, today’s circuit board has specific components, such as:
Layout and Circuit: PCB circuit is a tool for conducting between different components. A copper surface becomes the base and power layer. Besides, it involves routing through drawing.
Dielectric Layer In The Board: it is also known as the substrate that contains insulation that lies between the layers and a circuit.
Through-Hole Via: vias are made for conducting and a through-hole via helps multiple layers conduct. The plug-in of a device is a large through-hole. There is also a non-through-hole that helps in surface mounting and fixes screws while PCB assembly.
Solder Mask: The copper surface is not always tinned. Epoxy resin is used to print the non-tinned area to separate the tinned copper to prevent a short circuit. Solder mask has different colors, including black, green, red blue, etc.
Silkscreen or Marking: Silkscreen is used to make legends or mark names and locations of different components. It helps maintain a PCB after assembly.
Finishing: the copper surface has to be tinned or it would get oxidized. The surface finish involves different processes, such as ENIG, HASL, immersion tin or silver, and OSP. You can use any method according to your needs as each finishing method has some pros and cons.

Features of Advanced PCB

High-Density PCB’s
PCB is becoming advanced due to new technology. You will see the HDI circuit boards in all small gadgets. Both installation and ICs are also improving with time.
More reliable
Now, PCB is more reliable than before because we have better testing tools. Moreover, its manufacturing and the end product are of high quality.
Up To Parameters
Each PCB material has certain mechanical, electrical, physical, and chemical properties. You will get a high-performing PCB if its design is according to the standards and design parameters.
Better PCB Production
PCB production has also increased with time due to better tools, design software, and advanced technology. Various standards ensure a high-quality device, such as automation, standardization, management, etc. You will see better equipment to test your PCB to have a high-quality end product.
PC Board Assembly
Assembly has also improved and helps you to have more production than the previous years. Similarly, you can develop complete equipment by assembling different components.
PCB Maintenance
PCB maintenance is also essential, especially, if the assembly gets issues. You can easily replace the damaged parts, restoring the system. Making lightweight, and mini or smart PCB is also easier than before. You can have a device with high-speed signals by maintaining your circuit board.

Features of Integrated Circuit

The integrated circuits were developed by Jack Kilby and Robert Noyce. The integrated circuit is very common in certain industries, such as military, civil electronics, television, communication, radio recorder, computer, etc. It provides the following benefits.

  • Lightweight structure
  • Less lead
  • Small volume
  • Solder joint
  • More reliability
  • Longer lifespan
  • High performance
  • Mass production
  • Low cost

IC is a microelectronic component or device in a PCB. IC technology involves the manufacturing of chips, design technology, processing technology, testing, packaging, design innovation, and mass production.
The integrated circuit is a key part of advanced electronic sand it is the heart of many circuits. You will see at least one chip or IC in every electronic device. IC is a combination of various electronic components, including capacitors, resistors, transistors, etc. These components together make a small chip and are linked to having a common goal. There are different types of ICs, such as

  • Single-circuit logic gates
  • Voltage regulators
  • Open amps
  • Motor controllers
  • 555 timers
  • Microprocessors
  • Microcontrollers
  • FPGAs
  • Many others

There is a complex process of making layers of copper, semiconductor wafers, and several other materials. These materials interconnect to make resistors, transistors, and other parts of a circuit.
Not only IC is too small, but it has very thin copper layers and semiconductor wafers. The layers have very delicate connections. Similarly, The IC die is a very small circuit that is too tiny to connect or solder, so you have to package the die that converts the delicate die into a black chip that you often see.
You can enhance the working life of equipment by using the IC to assemble different electronic tools. It helps you to increase the assembly density many times compared to transistors.
These days, you would see silicon ICs involving semiconductors. So, IC is a device that integrates capacitors, resistors, semiconductors, and other elements that make a circuit perform certain tasks. The device connects wires between these components on the silicon wafer through oxidation, diffusion, aluminum evaporation, epitaxy, and photolithography, and then it is welded in a casing or shell.

Differences Between IC and a PCBoard
Differences Between IC and a PCBoard

What Is IC Package?

IC package helps convert a die into a device to have a connection. Die’s outer connection has a small gold wire to a pad on the package that helps to connect it. The pad or pin is silver and it is an extruded terminal on the IC that continues to connect to a circuit’s outer parts. There are different types of IC packages having different dimensions, installation methods, and a number of pins.
Understanding Pin Numbering and Polarity Marking
You should know that every IC is polarized and each pin is different in its function and location. So, the package must show each pin’s nature and function. Mostly the ICs have DOT or Notch to differentiate the first pin. Like, sometimes only one pin is the first or sometimes both are.
Package Mounting
The mounting of a package on a PCB also varies, it can be SMT or surface mount, SMD, or a through-hole mounting. The through-hole package is often large and easy to manage, and it is created to get stuck through a board’s one side and soldering the other side.
The surface mount package has different sizes, small or minuscule. These packages are created to be soldered to the PCB surface and sit on one side. The SMD package has pins either perpendicular to the chip or extruded out the side, or set in a matrix on a chip’s lower part. Such ICs are hard to assemble with hands and need special tools for this purpose.
Dual In-Line Package or DIP
DIP is an ordinary through-hole IC package having two parallel lines of pins that extend perpendicularly from a black, and rectangular plastic casing.
SMT, SMD, or Surface Mount Package
There are many types of SMT packages and in the case of ICs, you must have a custom PCB having compatible copper patterns to be soldered. You need special automated tools to solder the SMD package.
SOP or Small Outline Package
The SOIC package is the SMT cousin of the DIP as this is what you see when you bend all the pins outward on a DIP, reducing the size. The SOP package is very easy to solder with hands. The spacing between the pins should be 1.27mm or 0.05”.
The shrink small-outline package or SSOP is a small type of SOIC package. Likewise, there are TSOP or thin-small outline packages and TSSOP or thin-shrink small-outline packages.
It is easy to understand the difference between IC and PCB if you know all their features as described above.

Final Thoughts

The integrated circuit is a key part of advanced electronics and it is the heart of many circuits. You will see at least one chip or IC in every electronic device. IC is a combination of various electronic components, including capacitors, resistors, transistors, etc.
The purpose of the integrated circuit or IC is to integrate an ordinary circuit into a chip. So, if the IC gets damaged, the chip won’t work. But, if the PCB gets damaged, you can replace the components. However, PCB and IC work together to help an electronic device function.
Would like to know more about the ICs, PCBs or pcb assembly? Email us at sales@pnconline.com

PCB Design

Understanding the PCB Design for Half Adder

circuit board assembly, PC Board, pc board assembly, pcb assembly, pcb assembly near me, pcb assembly usa, PCB Design, Printed Circuit Board, , , , , ,

Multiple circuits’ combination involves various logic gates to create a multiplexer, encoder, de-multiplexer, and decoder. Such circuits have certain qualities, such as the circuit’s output more depends on the levels which are present at the input terminal.
Such a circuit lacks memory, and the previous input can’t influence the current input. The combined circuits consist of inputs and outputs.
A half adder is an electronic circuit that adds two binary numbers. So, two single binary numbers act as adders in this case. It can return the carry and the output, and the representation in practice involves the XOR and AND logic gates. There are two inputs in a half adder circuit, including A and B, generating the Sum and Carry. So, the number of outputs is also two in this case, like S and C.

Types of Combinational Circuits

  • Half adder
  • Full adder
  • Encoder
  • Subtractor
  • Decoder
  • Multiplexer
  • De-multiplexer

Understanding The Half Adder

Half adder is a digital circuit in PCB that provides an addition to binary numbers. In a half adder, a number’s weight is based on the binary digits’ position. The binary numbers are only from 0 to 1 of which 1 acts as the largest number and 0 as a smaller digit.
The two inputs of the half adder generate two outputs, so it is the simplest electronic circuit in the PCB. The inputs A and B are the bits where addition is required, whereas the Sum and Carry are the outputs abbreviated as S and C.

Half Adder Explained

The half adder circuit has two gates, including XOR and AND, and both have the same inputs. However, each gate generates the output, like XOR generates the Sum and AND generates Carry.

Half Adder Facts

According to engineers’ calculations if both ‘A and B’ inputs are 0, then both outputs like S and C would be 0.
However, if any of the input is 1, then the S or sum will be 1, but the C or carry will be 0.
However, if both A and B inputs are 1, then the S or sum will be 0, and the C or carry will be 1.
The half adder in a PCB performs additions according to the inputs applied.

2-Bit Half Adder

You can have the following combinations, such as

0+0=0

0+1=1

1+0=1

1+1=10

In this equation, 1+1=10, but it should be 2-bit output if rewritten, such as

0+0=00

0+1=01

1+0=01

1+1=10

In this case, the normal output is the Sum, whereas you should consider Carry as a carry-out. It is easy to implement a 1-bit adder through an XOR gate.
If you want to add two 8-bit, you can do it through the full adder because the half adder is suitable for the addition of one binary digit.
For two-binary digits, you will have to reduce the truth table. But, for a three-binary digit adder, the process of addition through a half adder should be done twice. Likewise, a four-digit adder involves another repetition of the half adder addition.
The entire process shows that it is easy to implement, but it takes lots of time.

Half-Adder IC

You can implement the half adder by using the high-speed CMOS digital and logic-based Printed Circuit Board.

Understanding Equation

It is easy to identify the equation of the half adder PCBs through two concepts, such as the Sum of Products, SOP, and the Products of sum, POS. The Boolean system of such PCBs helps find the relations between the inputs applied and the generated outputs.
Designers draw the K maps to find the equation and the maps are based on the facts. The k map has two equations, as it has two logic gates.

The K map for the Carry brings the below facts.
C=A.B
Whereas the K map for the Sum or XOR brings
S= A⊕ B

Applications of A Half-Adder PCB

The basic half adder has several applications, such:

  • It offers additions on the binary bits, and the logic unit and arithmetic lying in the computer need a half-adder circuit.
  • The half adder circuits when combined can produce full-adder circuits.
  • Such logic of half-adder circuits helps in designing calculators. So, the PCB in a calculator prefers a half-adder circuit.
  • The half-adder circuit also helps calculate tables and addresses.
  • Other than additions, the half-adder circuits can also handle different digital circuits’ applications. So, you can consider it a vital part of digital electronics.

Implementing The Half Adder Through An NOR Gate: NOR is a universal gate that helps implement a half adder.

Implementing The Half Adder Through NAND Gate

The NAND is also a universal gate that shows that you can design any type of PC Board through NAND gates. In this type, the carry output is produced through one NAND gate’s output being applied to the input which is another NAND gate. The second NAND gate is AND-gate generated output.

The Sum’s output equation can be produced through the output of the initial NAND, but with A and B inputs. In the end, the outputs generated by the NAND gates are again tried on the gate, producing the Sum’s output.
Hence, the standard adder in a digital PCB is easy to design through different logic gates. However, the addition of multiple bits is hard and it becomes a half-adder’s limitation.

Understanding A Full Adder PCB

The full-adder circuit includes three inputs, such as A, B, and C which add three numbers for input, generating the Carry and Sum. Whereas the number of the outputs is two. The main reason for half and full adders is the addition.
If Carry is produced through a previous addition, you can add it to another, unlike a half adder.

Difference Between A Half And Full Adder

A full adder involves two AND gates, two OR, and two EX-OR gates. Full adder is applicable in digital processors, and additions of several bits.
You have to combine two logic gates for PCB design with a half adder. But, a full adder consists of three gates.
Half adder is required in the electronic devices to calculate additions. But, the full adder is applied to the digital processors to add a long bit.
You can have a high output in full adders. Moreover, they involve a high speed and are very powerful in supplying voltage.
Full adder is also suitable for GPU, or Graphics Processing Unit.
How Are Half Adder And Full Adder Similar?
Half adder and full adder have one thing in common and that is the addition, as both are combinational circuits and don’t need a memory, like sequential circuits.

FAQs

What Is An Adder In PCB?

The digital circuits have different benefits, and if their main focus is to provide an additional, it is called Adder. It has two types, including the half adder and the full adder, depending on its inputs and output. However, the output is called Sum and Carry.
Adder is used in different kinds of processors other than just computers. They are constructed for several numerical elements, such as binary code decimal or excess-3.

Is There Any Limitation Of A Half Adder?

Yes, the half adder has some limitations. Like, it cannot add the carry bit produced from the previous or old bit. So, the half adders can’t perform additions in the case of multiple bits.

What Is A Full Adder In PCB?

A full adder includes three inputs, such as A, B, and C which add three numbers for input, generating the Carry and Sum. Whereas the number of the outputs is two.

Where To Use A Half-Adder Circuit?

PCB with a half adder is used in calculators and digital devices. It has a simple design and you can convert it to a half subtractor.

How Many Types Of Combinational Circuits Are There?

The types of combinational circuits include the half adder, full adder, encoder, subtractor, decoder, multiplexer, and de-multiplexer.

What Are The Uses Of A Half Adder?

A half adder offers additions on the binary bits, and the logic unit and arithmetic lying in the computer need a half-adder circuit. Moreover, half-adder circuits when combined can produce full-adder circuits. The logic in designing calculators. So, the PCB in a calculator prefers a half-adder circuit. The half-adder circuits can also handle different digital circuits’ applications.

Wrap Up

A half adder is an electronic circuit that adds two binary numbers. So, two single binary numbers act as adders in this case. It can return the carry and the output, and the representation in practice involves the XOR and AND logic gates. There are two inputs in a half adder circuit, including A and B, generating the Sum and Carry. So, the number of outputs is also two in this case, like S and C.
Would like to know more about pcb fabrication? Email us at sales@pnconline.com

Stencils for SMT Assembly

Stencils for SMT Assembly

PC Board, pc board assembly, pcb assembly, Printed Circuit Board, , ,

A stencil mask is used in many manufacturing processes to make PCBs. This includes SMT stencils which are most commonly used in the process of making printed circuit boards. The use of these SMT assembly varies based on the size and complexity of the board that they will be used on and the type of assembly machine that will be using them.
For any SMT stencil application, solder paste should be used for paste dispensing. Advantages of using a stencil method are high yield rate, high accuracy, and repeatability, low labor cost, and good surface finish. The main disadvantage is that it is not suitable for mass production or high-mix low-volume assembly.

SMT Stencil Types

There are two types of stencils, including manual and automatic. Manual stencils are available in many materials, such as stainless steel, plastic, etc., while the automatic ones are made from silicon rubber material which has been pre-impregnated with the conductive paste by screen printing methods. Both manual and automatic stencils require cleaning after each use.

Cleaning Process

The cleaning of stencils can be either by hand washing with solvents or ultrasonic cleaning bath. If an ultrasonic cleaner is used, then the dry time must be taken into consideration before reusing a stencil again to avoid a short circuit caused by excess moisture on metalized pads.

When an ultrasonic cleaner is not available, the cleaning process should take place immediately after soldering to prevent a short circuit due to moisture trapped under soldered components. It is also important to ensure proper drying of a Printed Circuit Board before applying the stencil. This will help reduce contamination during the next round of the soldering process.

How To Choose The Right SMT Stencils For Your Project?

You have to consider many factors when choosing an SMT stencil, including material, thickness, complexity, size, durability, and cost. It’s important to do your research before ordering a stencil from a vendor.

Stencil Application In PCB Assembly Method

The solder paste should be applied to both sides of a printed circuit board with a stencil. After applying solder paste, components are placed on top of it. Soldering is done by passing an electric current through it. This will melt solder paste, allowing it to flow between pads on PCB and component leads. This process is known as reflow soldering.
There are two types of reflow soldering, including hot air reflow soldering, and infrared reflow soldering. The hot air reflow soldering uses heated air to heat a PCB and components, while infrared reflow soldering uses IR lamps or IR guns to heat a PCB and components.
Both methods can be used for stencil applications. However, the hot air reflow soldering can only be used if there is no need to change the position of components after they have been placed on PCB. If there is a need to change the position of components after they have been placed on a PCB, then infrared reflow soldering must be used instead.

Stencils for SMT Assembly
Stencils for SMT Assembly

What Types of Designs Work with SMT Stencils?

While most customers using stencil printers are familiar with traditional SMT stencils, it’s important to know that there are other types of SMT stencil designs. While each is suitable for certain circuit board and component types, not all of them work with on-demand printing, so there are other factors to consider.
Another consideration when choosing an SMT stencil printer is whether or not you plan to print a single part or multiple parts at once. Most on-demand printers allow users to print one part at a time, but if you need more than one per run, it’s important to find a machine that can handle high volume runs, as well as quick turnaround times. If speed is your top priority, look for a system that offers a fast setup and take-down times so you can get back to production quickly.
Finally, be sure to choose a printer that offers interchangeable nozzles so you have access to different tip sizes without having to buy new machines. For example, if you want to use larger components like QFP packages or BGA chips, you might want a larger nozzle size.
Similarly, smaller components will likely require a smaller nozzle size. This allows you to switch between jobs quickly and easily instead of waiting for replacement parts to arrive. Of course, you should also make sure that your printer supports all of these features before purchasing.

How to Avoid Overruns on a PCBA?

Overruns occur when you place too many components on a single layer of your PC BOARD. This problem can be easily avoided by using stencil masks to help guide where your components should go. While it’s possible to manually transfer the component placement onto a new layer, it’s much easier and more efficient to use stencil masks. These plastic sheets are placed over each hole and etched with a laser, creating an accurate pattern that allows for easy placement of components onto layers below. This process ensures that all your components are placed correctly, which will result in fewer problems once you begin assembling your PCBA.
When there is not enough space between components, they may short out or interfere with one another. Both scenarios will negatively impact performance and may even damage some parts entirely. To avoid these issues, make sure you always use stencil masks to ensure proper spacing.
Additionally, check any design files you received from your manufacturer before placing components; sometimes oversights occur during translation. If you find errors while working with stencil masks, don’t hesitate to reach out to a service provider who can offer additional assistance if needed.

What Are Some Common Mistakes Made When Using SMT Stencils?

A stencil is an important part of manufacturing printed circuit boards, and you should choose it with care. Here, we will discuss some common mistakes when using SMT stencils so you can avoid them on your next project.

Not Knowing How Your Stencil Is Manufactured: There are three ways that stencils are made, such as laser-cut, die-cut, and silkscreen. The first two are much more expensive than silk screening but they produce higher-quality results. Silk screening has been around for decades and allows people without special equipment to create professional-looking stencils that work well for mass production. However, they don’t last as long as other stencils.

Not Checking Your Board for Burrs before Using a Stencil: A burr is a small piece of metal leftover from cutting your board with a laser cutter or CNC machine. It can easily ruin your stencil and make it unusable. You should always check for burrs before using a stencil, and make sure you get rid of them by filing them down with an emery board or some other method if they are present.

Not Pressing the Stencil Firmly against PCB: If you don’t press firmly enough against your board when applying solder paste, there will be air pockets where components won’t be soldered properly. This may not seem like a big deal at a first glance, but it can cause issues later on that could cost you time and money. You should always make sure to press firmly against your stencil before starting to apply solder paste so you get high-quality results every time.

Using a Stencil That Is Too Small for Your Project: When using a stencil for SMT placement, it is important to choose one that is large enough for all of your components. If you try to use a stencil that is too small, you will end up with extra solder paste on your board and possibly even miss-placed components. You should always make sure you are using a stencil that has plenty of room for all of your parts so you don’t waste time or money trying to fix mistakes later on.

Not Cleaning the Board after Use: After you have finished soldering, you should clean off any excess solder paste from your board. If left on there too long, it can cause oxidation and other issues which could ruin both your board and stencil. You should always clean off your board after using a stencil to make sure you don’t run into problems later on.

Using A Stencil That Is Too Old: While they may seem like they last forever, SMT stencils do wear out over time. You should always make sure to replace them when they start showing signs of wear and tear. Signs that your stencil is worn out include warped edges or holes that are too large for your components. If you see these kinds of problems, it’s best to get a new one before continuing with your project so you don’t end up wasting money or having issues later on.
FAQs

Will My SMT Stencil Last Forever?

No matter which type of stencil you purchase, it won’t last forever. Eventually, all stencils will degrade and lose their effectiveness.

What Happens when an SMT Stencil Gets Damaged?

Damaged stencils pose a serious risk because they could cause solder paste to leak through and contaminate nearby components. This can result in costly repair work and even downtime for your production line.

How Do I Test My SMT Stencil to See If It’s Working Properly?

To test your stencil, you can use a device called a stencil tester. You can also get professional help in this case.
Would like to know more about SMT Stencils in PCB or PC Board assembly? Email us at sales@pnconline.com