日志

What is the TG value of PCB and how to choose?

12/05/2023 在： /通过：

It is well known that the base material polymer or glass) is changing from a glassy, solid, rigid state to a rubbery state when the temperature rises to a certain region, so the temperature at this point is called the glass transition temperature (Tg). In other words, Tg is the mechanical property that specifies the glass transition temperature, i.e., the maximum temperature at which the glass remains rigid.

TG in PCB boards means temperature resistance. the higher the Tg point, the higher the temperature requirement when pressing the board, the harder and more brittle the board will be, which will affect the quality of the mechanically drilled holes to a certain extent in the subsequent process.

PCB board TG value classification

Common board TG value can be roughly divided into three major categories:

TG130: general TG value of the board, temperature resistance of about 140 ℃, common such TG value of the board is Sheng Yi S1141 and Kingboard KB-6164F

TG150: Medium TG value plate, temperature resistance 150℃~170℃, common such TG value plate is SangYi S1141 150 and Kingboard KB-6165F.

TG170: Higher TG value boards, temperature resistance above 170℃, common such TG value boards are SangYi S1170 and Kingboard KB-6167F, the cost of higher TG value boards is also relatively high.

How to choose pcb with different TG values?

PCBs with different TG (glass transition temperature) have their own advantages and application scenarios, which one is the best to choose depends on the specific application needs. The following are some common TG PCBs and their characteristics.
1.FR-4(TG 130°C-180°C):FR-4 is one of the most common and widely used TG PCB circuit board materials. It has good mechanical strength, electrical properties and heat resistance.FR-4 is suitable for most general applications of electronic equipment and is relatively low cost.

2. High TG PCB ( TG 150°C-200°C):High TG PCBs have a higher glass transition temperature than regular FR-4, providing better stability and reliability in high temperature environments. They are suitable for applications that require operation in high temperature environments, such as automotive electronics, industrial controls and aerospace.

3. High Frequency TG PCBs: High Frequency TG PCBs are designed for high frequency signal transmission with excellent impedance control and signal integrity. These boards are typically made of low dielectric constant and low loss materials to ensure optimal signal transmission.

4. Metal Substrates:Metal Substrates are a special type of TG PCB that has a layer of metal (usually aluminum or copper) covering the substrate for heat dissipation and conductivity. Metal substrates are suitable for high power applications, LED lighting and power electronics where good thermal performance is required.

The best choice of TG PCB depends on your application needs, such as operating environment, signal requirements, temperature requirements, cost constraints, etc.

The basic characteristics and development prospects of FR4 pcb material

11/27/2023 在： /通过：

FR4 glass epoxy resin is currently the most used substrate in the pcb market. more than 80% of the pcb is manufactured with FR4, what is FR4, what are its characteristics, this article will focus on giving you an introduction.

FR4 is a glass fiber epoxy resin copper cladding board, it is based on chlorite, quartz sand, limestone, dolomite, boron calcium stone, boron magnesium stone six kinds of minerals as raw materials by high temperature melting, drawing, winding, weaving and other processes manufactured. The diameter of its monofilament for a few microns to more than two dozen microns, equivalent to a hair strand of 1/20 ~ 1/5, each bunch of fiber raw silk is composed of hundreds or even thousands of monofilaments.
The FR prefix refers to the flammability rating of the resin system used in the laminated composites that make up the substrate of a printed circuit board. The addition of bromine compounds to the resin produces flame retardant properties that are self-extinguishing and combustible.

FR4 Basic Characteristics

●Vertical laminar bending strength A: normal: E-1/150, 150±5℃≥340Mpa

●Parallel laminar impact strength (simply supported beam method): ≥230KJ/m

●Insulation resistance after water immersion (D-24/23): ≥5.0×108Ω

●Vertical laminar electrical strength (in 90±2℃ transformer oil, plate thickness 1mm): ≥14.2MV/m

●Parallel layer to the breakdown voltage (in 90 ± 2 ℃ transformer oil): ≥ 40KV

●Relative dielectric constant (50Hz): ≤5.5

●Relative dielectric constant (1MHz): ≤5.5

●Dielectric loss factor (50Hz): ≤0.04

●Dielectric loss factor (1MHz): ≤0.04

●Water absorption (D-24/23, plate thickness 1.6mm): ≤19mg

●Density: 1.70-1.90g/cm³.

●Flammability: FV0

What are the properties of FR4 substrates?

Flame Retardant

Chemicals used on materials to prevent or retard the spread of fire are known as flame retardants.FR4 substrates have excellent thermal, mechanical and electrical properties, making them perfect for a wide range of electronic applications. Flame retardant laminates and prepregs are very versatile, suitable for a variety of manufacturing procedures and produce predictable results.

Good Electrical Properties

The electrical properties of PCB materials are critical to signal integrity and impedance considerations. They determine how quickly an electrical signal can propagate through the material and how much charge it can retain in a given volume.

Low Moisture Absorption

Moisture absorption is the ability of a PCB material to resist absorbing water when immersed in water. It is given by the percentage increase in weight of the circuit board material due to water absorption under controlled conditions.FR4 material has a low moisture absorption of 0.10% after 24 hours of immersion in water.

 

Limitations of FR4 circuit board materials

FR4 has been used in printed circuit boards for many years. It is inexpensive and provides adequate electrical insulation. However, when FR4 is used in high-speed applications, the following problems may occur:

Insulation Stability
Although FR4 is a good insulator, it has its limitations when subjected to high power, high voltage or high heat. If certain limits are exceeded, the insulating properties of the material will deteriorate and they will begin to conduct electricity. This can lead to board failure.

Controlled Impedance
FR4 does not provide a uniform dielectric constant like high speed circuit board materials. As frequency increases, Dk changes. While high-speed materials have a dielectric constant tolerance of less than 2%, FR4 has a tolerance of up to 10%. the change in Dk in FR4 poses a challenge while maintaining the impedance value. Therefore, this material is not a preferred choice for controlling impedance boards.

Signal Loss
Signal loss is an important aspect of PCB design, especially in high-frequency applications.FR4 is not the best material for these applications because it has a larger Df (dissipation factor) than high-frequency materials.

FR4 Performance Classification

Standard F4
Baseline electric grade F4 epoxy glass provides the most economical, general purpose substrate for typical consumer electronics and digital circuit boards without pushing extreme frequency limits.

High Frequency F4
Multi-glass bodies like rf-35 control dielectric values below +/-0.05 across the microwave region. These tightly aligned low loss materials become critical to RF device integrity.

High Temperature F4
Through resin modification or bismaleimide-triazine blends, some FF4 formulations withstand temperatures above 230°C to meet the needs of aerospace and automotive electronics equipment.

Highly reliable F4
Isola’s “HR” family and Allen family 85N laminates utilize high resin content and glass weaving to punch holes in multilayers and are elastically rigid designed to resist crack propagation.

Development Prospect of FR-4 Copper Clad Laminate

FR-4 copper clad laminate is the core material of printed circuit boards, which is widely used in electronics, communications, computers, automotive, aerospace and other fields. With the development of 5G, Internet of Things, intelligent manufacturing and other emerging industries, FR-4 laminates have a very broad market outlook.

First of all, the development of 5G will promote the demand for FR-4 laminates, 5G communication technology requires superior high-frequency transmission performance, so the performance of FR-4 laminates also need to be improved. For example, the dielectric constant of the sheet needs to be increased and the dielectric loss of the sheet needs to be reduced. In addition, the miniaturization and lightweight of 5G equipment also put forward higher requirements for the performance of FR-4 boards, such as the need to optimize the thickness of the board. Therefore, with the rapid development of 5G in the future, FR-4 copper cladding board market demand growth prospects.

Secondly, the widespread application of the Internet of Things (IoT) will also drive the growth of FR-4 copper-clad laminates market demand. The Internet of Things requires higher performance indicators (such as high-frequency transmission, high-speed transmission, etc.), in addition to the miniaturization of the Internet of Things terminal equipment requires thinner and lighter FR-4 copper cladding boards, which will promote the FR-4 cladding board market demand continues to increase.

Again, the rapid development of intelligent manufacturing will have a positive impact on FR-4 laminate market demand. Intelligent manufacturing has become a national strategy, the transformation and upgrading of the manufacturing industry requires more intelligent equipment. These devices require high-speed transmission of high-frequency transmission and other performance indicators such as stringent FR-4 copper cladding boards, the market demand will also continue to increase.

FR4 has been widely used in electronic equipment for its high reliability, good processability, heat resistance and excellent electrical properties. Its dielectric constant and dielectric loss angle tangent and other electrical performance parameters are controlled with high precision, which can ensure stable signal transmission. In addition, FR4 sheet has good thermal stability and can remain stable in high-temperature environments, making it suitable for applications under various environmental conditions. Therefore, FR4PCB is an excellent electronic material, providing a strong guarantee for the performance and reliability of electronic equipment.

Function and application of solar charging controller

11/21/2023 在： /通过：

The solar charging controller is used in the solar power generation system. It controls the automatic control equipment of the multi -way solar cell square matrix to the battery charging and the battery to the solar inverter. It stipulates and controls the charging and discharge conditions of the battery, and controls the electric energy output of the load and the battery to the load according to the power supply requirements of the load. It is the core control part of the entire photovoltaic power supply system.

Type of solar charging controller

1. Ordinary solar controller: This is the first generation of technology. The working principle is to directly hang the output of the solar panel to the battery port. When the battery is sufficient, it is disconnected. Because of the internal resistance of the battery, it is difficult to fill up the battery, and the solar panel is not fully utilized. The MPPT tracking efficiency is only 70 ~ 76%, which has been eliminated by the market, and it is basically used.

2.PWM Solar Controller: This is the second -generation technology. Now the market is the most. The working method is to use the PWM control method. Compared with the ordinary solar controller, it has improved a lot. It can solve the problem of battery dissatisfaction. MPPT tracking efficiency It is 75 ~ 80%, but solar panels are not fully used.

3.Mppt Solar controller: MPPT is the abbreviation of the maximum power point tracking. The MPPT charging controller adjusts the battery charging voltage and current by tracking the maximum point of the output power of the solar panel, thereby achieving the charging control of the battery. It is efficient and intelligent. , Accurate features.

Features of Solar Charge Controller

Solar charge controllers come with a variety of features and functions to enhance the performance and protection of the solar power system. Here are some key features you might find in these controllers:

Battery Temperature Compensation

Battery temperature compensation is a critical feature that adjusts the charging parameters based on the ambient temperature. This helps prevent overcharging in high temperatures and ensures adequate charging in cold conditions, extending the battery’s lifespan.

Overload and Short Circuit Protection

Most solar charge controllers include built-in protection mechanisms to safeguard the system from overloads and short circuits. These safety features prevent damage to the controller, battery, and connected devices.

LED/LCD Display

Many modern charge controllers are equipped with LED or LCD displays that provide real-time information about the system’s performance. Users can monitor battery voltage, charging current, and other relevant data at a glance.

USB Ports

Some charge controllers come with USB ports, allowing users to charge small electronic devices directly from the solar system. This feature can be invaluable during power outages or when off-grid and when in remote locations.

Communication and Data Logging

Advanced charge controllers can be connected to a computer or smartphone for remote monitoring and data logging. This enables users to track the system’s performance over time and make adjustments as necessary.

Function of solar charging controller

The main functions of solar charging controller include:

1. Power adjustment function: Through MPPT technology, control the output power of solar panels to achieve adjustment of battery charging voltage and current.

2. Communication function: Solar charging controllers can exchange data through communication interfaces with other devices (such as battery management systems, charging piles, etc.) to achieve remote monitoring and control.

3. Protection function: Solar charging controller has a complete protection function, which can protect the battery overcharge and release, extend the life of the battery, prevent the solar battery square, the power of the battery, and prevent the load and controller and other other. Internal short circuit of the device.

4. Self -check function: When the controller is affected by natural factors or artificial operation, it can allow the controller to self -check, let people know whether the controller is intact, and reduces many unnecessary working hours.

5. Restore interval function: It is a recovery interval made by overcharge or overlap protection to avoid the work jitter of load caused by wire resistance or self -recovery characteristics of batteries.

6. Temperature compensation function: monitor the temperature of the battery, modify the recharge and let the battery work in an ideal state.

7. Optical control function: Mostly used for automatic lamps. When the environment is bright enough, the controller will automatically turn off the load output; and the load will be automatically turned on after the environment is dark to realize the automatic control function.

Application of solar charging controller

Solar charge controllers are a vital component in various solar energy applications. Here are some of the primary uses of these controllers:

Off-Grid Solar Systems

Off-grid solar systems, which are not connected to the utility grid, rely on solar charge controllers to regulate the charging and discharging of batteries. This ensures a steady power supply even when the sun is not shining.

Grid-Tied Solar Systems with Battery Backup

Grid-tied solar systems with battery backup use charge controllers to manage the battery storage component. These systems can store excess energy generated during the day and use it during grid outages or during peak demand periods to reduce electricity costs.

Solar Street Lighting

Solar charge controllers are used in solar street lighting systems to manage the energy flow between the solar panels, batteries, and LED lights. They ensure efficient energy utilization and help extend the lifespan of the batteries.

Remote Monitoring and Telemetry

Solar charge controllers are also employed in remote monitoring and telemetry systems, such as those used in weather stations, communication equipment, and data loggers. These controllers enable reliable power supply in remote locations.

The role of solar charging controllers in the field of new energy

The role of solar charging controllers in the field of new energy is very critical. As an important part of the solar photovoltaic power generation system, the solar charging controller is responsible for effectively controlling the electrical energy generated by the solar panel to ensure that the charging and discharge process of the battery is safe and reliable. It monitors the voltage and current of the battery to achieve intelligent management of the charging process. When the battery is fully charged, the controller will automatically cut off the charging to prevent overload; when the battery is insufficient, the controller will automatically cut off the load to prevent override. This can not only protect the batteries from damage to excessive charging and excessive discharge, but also improve the efficiency of the use of electricity.

In addition, the solar charging controller can also achieve maximum power point tracking (MPPT) function, so that the solar panel is always output at the maximum power to improve the charging efficiency. This helps reduce energy loss and improve the overall efficiency of the system.

In the field of new energy, solar charging controllers are widely used in scenarios and other scenarios of separation power generation systems, grid -connected power generation systems, and electric vehicle charging stations. In these scenarios, solar charging controllers can not only provide safe and reliable charging control for batteries, but also provide stable power supply for loads. This makes solar energy a reliable and sustainable source of energy, and has made positive contributions to the development of green energy and reducing carbon emissions.

It should be noted that with the continuous development of new energy technology, the performance and functions of solar charging controllers are constantly being upgraded and improved. In the future, with the further development of the new energy field, solar charging controllers will be applied in a wider range of fields, making greater contributions to promoting the transformation of global energy structure and achieving sustainable development.

SMD Soldering Guide: Technology Sharing

11/15/2023 在： /通过：

SMD (Surface Mount Device) is a packaging method for electronic components that uses surface mount technology to solder electronic components to the surface of a circuit board. This type of packaging is characterized by small size, light weight, material saving, high reliability and powerful performance.SMD soldering involves placing electronic components in specific locations on the circuit board and then soldering them by melting the solder to firmly connect the components to the board.

SMD Soldering Tools

Surface mount device soldering requires some specialized tools in order to handle tiny components and make precision solder joints. Here are some of the essential items you’ll need:

Soldering Iron – A fine-tipped soldering iron in the 15-30W power range is ideal for SMD work. Tips as small as 0.5mm can be used. Temperature control features help avoid overheating.

Solder paste– Solder paste consists of a mixture of powdered solder alloy and flux cream. It allows solder to be precisely applied to SMD pads before components are placed.

Microscope – A stereo microscope or magnifying glasses are indispensable for inspecting small solder joints and component placement. A microscope with 20x to 40x magnification is typical.

Tweezers – Fine-tip tweezers allow precise handling and placement of SMD components as small as 0201 or 01005 sizes (0.25mm x 0.125mm). Anti-static tweezers are preferred.

Soldering Helping Hands – Helping hands tools with magnifying lenses allow hands-free positioning of PCBs under a microscope during soldering.

Stencil–PCB stencils are thin metal sheets laser-cut with a pattern of openings matching the PCB’s solder pad layout. To apply solder paste, the stencil is aligned to the PCB and the paste is screened onto the pads through the stencil’s openings. Using a stencil allows precise and efficient solder paste application prior to SMD component placement.

Jigs – Jigs help position boards at an angle which improves visibility and access to solder joints underneath components during hand soldering.

Solder Sucker/Desoldering Tools – Specialized vacuum tools are used to remove or rework solder joints and desolder components for repair work.

Surface Mounting Steps

▶Mounting the substrate: Fix the substrate on the countertop.

▶ Point paste or glue: according to the size of the components, the SMD adhesive coated in the pre-determined position, if the assembly process using reflow soldering, it is necessary to apply the paste in the substrate pads, the current commonly used in the medium-high temperature level Sn-Ag solder paste.

▶ Mounting of SMD: Generally, automated professional mounter is used, which mainly includes: suction and loading head for picking and placing SMD, X-Y working table, program control system and feeding part.

▶ Thermal curing: carried out after the dispensing, SMD, under a certain temperature, time control through the curing oven to make the adhesive curing. The curing oven is controlled by a certain temperature and time to improve the adhesive strength of the SMD, and to avoid the components being shifted by vibration and shock during storage and transportation.

▶ SMD soldering: Wave soldering with SMD adhesive bonding and reflow soldering with solder paste bonding are used.

▶Cleaning: Remove residual adhesive to prevent corrosion of the substrate.

▶Inspection and testing: Solderability is inspected according to standards and test requirements.

SMD soldering needs to pay attention to the following points:

1. Keep the soldering iron tip clean to avoid oxidizing or staining its surface with impurities, which may hinder the heat conduction between the tip and the soldered parts.

2. Before soldering, solder paste should be evenly applied to the pads of the PCB, and make sure that the amount of solder paste applied is appropriate.

3. Components should be accurately placed on the PCB to avoid misalignment or tilting.

4. The temperature of the reflow oven should be strictly controlled to ensure that the solder paste melts and solidifies at the correct time and position.

5. The soldering time should be properly adjusted to ensure the quality of soldering.

6. Soldering pressure should be properly adjusted to ensure the density and strength of the solder.

7. Reflow soldering process parameters should be strictly controlled, including the temperature, time and pressure of the preheating zone, uniform heat zone, reflow zone and cooling zone.

8. The welding environment should be kept clean to avoid external factors interfere with the welding quality.

9. Process inspection should be carried out to ensure that the welding quality meets the requirements.

Common SMD package size

Common SMD mounting method is divided into SO mounting, QFP mounting, LCCC mounting and PLCC mounting four.

(1) SO mounting is divided into SOP mounting and SOL mounting, the use of wing-shaped electrode pin shape, pin spacing 1.27mm, 1.0 m m, 0.8mm, 0.65mm and 0.5mm.

(2) PQFP mounting rectangle on all sides of the wing-shaped electrode pins, the thickness of 1.0mm or 0.5mm. QFP packaged chips are generally large-scale integrated circuits, the number of electrode pins for the 20 to 400, the minimum pin pitch is 0.4mm, the largest is 1.27mm.

The minimum pin spacing is 0.4mm and the maximum is 1.27mm.

(3) LCCC mounting is not a pin mounting, the chip is mounted on a ceramic carrier, no lead electrode soldering ends are arranged on the bottom of the four sides of the mounting surface, the number of electrode pins 18 ~ 156, the spacing of 1.27mm.

(4) PLCC mounting is a rectangular mounting of integrated circuits, its pins hooked back to the inside, the number of electrode pins 16 ~ 84, the pitch is 1.27mm.

SMD soldering is a very delicate work, which is nowadays done by fully automated production lines. Of course, for beginners to understand and learn manual welding is also very necessary. Because this way we can more quickly familiar with the entire welding process, and better able to find problems, solve problems.

How to choose the plating and thickness of the PCB board?

11/09/2023 在： /通过：

Once the board has passed through the standard PCB manufacturing process, the bare copper in the PCB is ready for surface treatment.PCB plating is used to protect any copper in the PCB that would be exposed through the soldermask, whether it be pads, vias, or other conductive components. Designers usually default to tin-lead plating, but other plating options may be better suited for your board application.

In this article, I will cover the different PCB plating material options and their advantages in PCBs. There are a variety of options available and depending on your reliability or application needs, you may want to check if the manufacturer can apply the plating you need in your design. We will look at these options and briefly discuss how plating affects loss.

Types of PCB Plating

There are a variety of PCB plating materials. I have summarized the popular materials that designers should know and understand in the following sections. I have never met a manufacturer that does not offer all of these options. If your target manufacturer does not explicitly state that they offer one of the options in the list below, you can always email them for a list of their capabilities, including their PCB plating material options.

Tin Lead and Immersion Tin Plating
This PCB finish may be the least expensive option, but it is not RoHS compliant due to the use of lead in the plated finish.Dip tin is a lead-free alternative for entry-level boards.

Advantage:
▶ Ultra-flat surface
▶ Inexpensive
▶ Compatible with standard solder

Disadvantages:
▶ Not conducive to multiple assembly processes or rework
▶ Forms tin whiskers over time
▶ Tin diffusion into copper may reduce shelf life depending on intermetallic compound content
▶ May damage soldermask during plating process

 

Hot Air Solder Leveling (HASL) and Lead Free HASL
HASL was once a very popular finishing option, but it is not as reliable as other plating materials. It is inexpensive and has a lead-free option, so it can be used as an entry-level plating option.
Advantage:
▶ Inexpensive
▶ Can be repaired
▶ Due to poor wettability

Disadvantages:
▶Uneven surface makes it less useful for small SMD devices
▶ May be damaged by thermal shock
▶May be difficult to solder

 

Electroless Nickel Immersion Gold Plating (ENIG)
Considering the drawbacks of SnPb and immersion tin plating, ENIG is now arguably the most popular surface treatment in the industry. In this plating material, nickel acts as a barrier between the copper and the thin gold surface layer of the component to be soldered.

Advantage:
▶ Ultra-flat surface
▶ PTH holes can be easily plated
▶ Widely available
▶Easy soldering
▶Suitable for fine-pitch components
▶Highly reliable against mechanical damage
▶Wire bondable (aluminum)

Disadvantages
▶ Not favorable for multiple assembly processes or rework
▶ May experience phosphorus penetration between gold and nickel layers, known as black pad syndrome
▶ Rough interfaces can cause signal loss at high frequencies

 

Organic Solderability Preservative (OSP)
This organic, water-based finish selectively binds to copper to provide a highly flat surface finish. As an organic material, it is sensitive to handling and contaminants, although the application process is simpler than other PCB plating materials. It also has very low losses at high frequencies.

Advantage:
▶ Ultra-flat surface
▶ Repairable after application
▶Simple application process
▶Very low interconnection loss at high frequencies
▶Wire bondable (aluminum)

Disadvantages:
▶Easy to damage
▶Short shelf life

 

Immersion Silver Plating
This is my preferred PCB plating material for high frequency applications. It forms a smooth interface with the bare copper and therefore does not increase conductor losses as other PCB finishes do. The main disadvantage is that it loses its luster on the bare board, so it should be soldered and encapsulated as soon as possible after fabrication.

Advantage:
▶ Easy aluminum soldering and wire bonding
▶ Ultra-flat surface
▶ Suitable for fine pitch
▶ Better suited for high-frequency interconnections in high-reliability systems
▶Wire bondable (aluminum)

Disadvantages:
▶ Silver whiskering over time
▶Exposed (unsoldered) conductors lose luster over time, although added OSP helps prevent this ▶May be difficult to plate into small-diameter vias

 

Hard Gold
This plating material is essentially ENIG, but has a very thick outer layer of gold, making it one of the most expensive PCB plating materials. The gold layer creates a hard surface that can be damaged, but its thickness makes it difficult to fully expose the nickel layer.

Advantage:
▶ Wire bondable (aluminum and gold)
▶ Very durable surface

Disadvantages.
▶ Very expensive
▶ Not applicable to solderable areas
▶ Requires additional process steps for selective applications
▶ May experience brittle cracking

 

How to specify PCB plating material and thickness

Typical PCB plating thickness values are about 100 micro inches. For immersion silver and OSP, typical thicknesses can be as low as about 10 micro inches. If you are producing a prototype and the manufacturer has a standard quotation, you will have the opportunity to specify the type of plating on their forms. On these forms, they may not ask you to provide the thickness, so be sure to specify it if you need a specific thickness. After specifying the desired plating value, your manufacturer will need to ensure that the plating can be reliably deposited to the desired thickness.

Why is the thickness of the plated material important? There are two reasons. First, the IPC-2221A standard specifies minimum plating thicknesses for each IPC product category (see Table 4.3). If you want your product to comply with any of the standard IPC product categories, then you need to make sure that the plating thickness meets its specifications. Normally, if you specify the product category, as you normally do in your manufacturing notes, the minimum plating thickness will be implied. Just make sure you don’t contradict yourself, otherwise the manufacturer will email you asking for plating comments.

Another reason to worry about PCB plating thickness is its effect on losses. At low frequencies, you probably won’t notice any effect on frequency, so low-speed digital signals and sub-GHz radios don’t need to worry much about PCB plating thickness. I’ve completed custom printed transmitters running at 5.8GHz WiFi with ENIG (not the best choice for high frequencies) that swamped the receiver in our test setup, so if your circuit design is correct, you can even bypass most plating at these frequencies.

The loss problem arises at millimeter-wave frequencies, such as short-range radar (24 GHz) and higher. At these frequencies, the roughness of the copper becomes a very noticeable factor in loss, especially on low loss RF substrates like Rogers. The thickness of the plating will determine the roughness experienced by the signal as it propagates, and this will be reflected in the skin effect resistance.

How to cut PCB (the latest guide)

11/07/2023 在： /通过：

The PCB required for different electronic products is also different. How to match the compatible shape requires cutting PCB. How to cut PCB into the required size, and then introduce the PCB cutting guide in detail.

Why we need to cut pcb ?

There are several reasons why you might want to cut your PCB to the right size for your current project. Many projects require PCB sizes and dimensions that are not readily available. In these types of cases, cutting the size you need from a larger PCB might be the only option.

Moreover, a lot of professionals and enthusiasts prefer ordering larger PCBs and cutting custom sizes. This is a common practice as larger PCBs often cost less per unit of size. Therefore, this practice can help make projects more economical and cost-effective.

Cutting your own custom-sized PCBs can also help you save time. If you are in the middle of a time-critical project and have large PCBs lying around, cutting the size you need gives you access to the right board immediately. This way, you do not have to waste time waiting for custom-size boards to arrive from your supplier.

How to cut PCB

There are many ways to cut the circuit board. The following are the main methods:

1. Cutting: Cutting is the first step of the mechanical operation of the printed circuit board. By cutting, it can give a rough shape and outline. The basic cutting method is suitable for a variety of substrates, usually the thickness does not exceed 2mm. When the cutting board is more than 2mm, the edges of the cut will appear rough and uneven, so this method is generally not adopted.

2.V cutting machine: Most factories use special V -type cutting machines for PCB cutting.

3. Template and Punching: Use the template to form a groove around the PCB material, and then use the punch to break the PCB. However, this method may lead to cracks in the final product and lower efficiency.

4. PCB router machine, V-CUT PCB machine, PCB milling cutter, PCB sawing machine, dedicated PCB cutting tool: These tools may be more applicable when dealing with PCB of different materials and sizes.

PCB cutting process

1. Determine the cutting position: Before cutting, you need to determine the position and shape of the cut. This can help determine by using templates or manual drawing.

2. Select the right cutting tool: Select the appropriate cutting tool according to the PCB material and size of the cut. Common cutting tools include V-CUT machines, PCB router machines, PCB milling cutters, PCB sawing machines, etc.

3. Adjust the cutting depth: For some PCBs that need to be cut into a certain depth, you need to adjust the cutting depth. This can be achieved by setting the cutting depth of cutting or using the template on the cutting machine.

4. Control the cutting speed: When cutting, you need to control the cutting speed to avoid excessive or insufficient cutting. Generally speaking, the slower cutting speed can provide better cutting quality and less calories.

5. Use coolant: When cutting, you can use coolant to help reduce temperature and reduce the production of thermal stress. This can prevent the PCB board from deforming or rupturing.

6. Check the cutting quality: After the cutting is complete, check the cutting quality to ensure that the cutting meets the requirements. If the cutting is poor, you can adjust the cutting tool or re -adjust the cutting parameters.

Cutting is an important process of PCB assembly. Correct cutting can better complete the product assembly. For enthusiasts, knowing how to cut PCB is beneficial, because it can help save the cost and time of major projects. With this guide, you should be able to learn how to cut PCB, what tools do you need, and how to use them to achieve the best results.

How to choose a PCB assembly company

11/06/2023 在： /通过：

Choosing a correct PCB assembly company can quickly complete your PCB project, and at the same time to ensure the quality of the product. The PCB project reaches the assembly stage, indicating that you have invested a lot of time and resources, so it is important to choose the correct assembly company. Good partners can help you reduce costs in all aspects. How to choose the correct assembly company takes time to inspect. Today we will discuss the steps of choosing PCB assembly companies.

What are the content of PCB assembly?

PCB assembly includes the following content:

1. Circuit board composition: The circuit board is mainly composed of pads, perforated, installation holes, wires, components, plug -in plug -ins, filling, electrical boundaries, etc.

2. Welding of components: Welding the component through the pad on the circuit board.

3. Layout of components: According to the function and design requirements of the circuit board, the component is reasonably layout on the circuit board.

4. Connection of the wire: According to the circuit diagram and design requirements, connect the wire correctly between the pads and components of the circuit board.

5. Fix the installation hole: On the back of the circuit board, make some installation holes as needed to fix the circuit board to the chassis or bracket.

6. Fill and coverage: Fill in some parts of the circuit board to fill the insulating material to protect the circuit board from environmental effects, and at the same time, it can also improve the mechanical strength of the circuit board.

7. Test and debugging: After completing the assembly, test and debug the circuit board to ensure that its functions are normal.

Select the steps of PCB assembly company

Determine the needs

Each PCB project is different, so the solution will be different. Therefore, when negotiating with PCB companies, you must first clear the needs and spend more time to improve the project.

Determine the experience level of PCB assembly company

Experience is another important factor to determine the choice of PCB assembly companies. An experienced company will stimulate confidence and trust. This is because they have professional teams to ensure high -quality PCBA and fast turnover time. If you want to know the experience of a company, you can go to their website to see, or talk to them directly with them.

Confirm the qualifications and certification

Ensure that the selected PCB assembly company has relevant qualifications and certifications, such as ISO 9001 quality management certification and UL certification, which can ensure the quality of the product and meet the relevant standards.

Confirm the production capacity

It is necessary to understand the production capacity of the PCB assembly company, including the number of production lines, the modernization of equipment, and the level of employee’s technical level to ensure that the production tasks are completed in a limited time and delivered in time in time.

View experience and reputation

Choosing a PCB assembly company with rich experience and good reputation can ensure the quality and reliability of product quality and delivery. You can learn its experience and reputation by viewing the manufacturer’s historical orders and customer evaluation.

Confirm the price and service

Choosing a PCB assembly company with reasonable prices and good services can reduce procurement costs and improve the procurement experience. It is necessary to consider factors such as manufacturers’ prices, after -sales service and distribution methods.

View technical ability

Choosing PCB assembly companies with high technical capabilities can ensure product quality and meet technical requirements. Considering factors such as manufacturers’ technical research and development strength, innovation ability, and patent quantity.

Examine the factory environment and equipment

Choose a PCB assembly company with modern equipment, clean process workshops and good production environment.
Examination of quality management system: Choosing a PCB assembly company with a complete quality management system and a ISO9001 certification company can ensure product quality and stability.

Dating and after -sales service

Choosing PCB assembly companies with small stress and good after -sales service can ensure the timelyness of the order and the quality of after -sales service.

By following these steps, you are much more likely to discover PCB assembly companies who will take care of your project. There is no company more qualified to do so than EEI Manufacturing. With expertise in PCB assembly services and a passion for customer satisfaction, we assure you that you will be pleased with the result of your project.

How to layout high frequency pcb

11/03/2023 在： /通过：

High-frequency PCB refers to the electromagnetic frequency of the higher special circuit boards for high-frequency (frequency greater than 300MHZ or wavelength less than 1 meter) and microwave (frequency greater than 3GHZ or wavelength less than 0.1 meters) in the field of PCB, is in the microwave substrate copper-clad laminate boards on the use of ordinary rigid circuit boards manufactured using some of the process or the use of special treatment methods and the production of circuit boards. High-frequency circuit board circuit design is a very complex process, the layout of each line must be in place, the next will focus on high-frequency circuit board layout methods.

How to layout high frequency pcb？

1. Multilayer board wiring

High-frequency circuits are often highly integrated, wiring density, the use of multi-layer board is both necessary for wiring, but also an effective means of reducing interference. In the PCB Layout stage, a reasonable choice of a certain number of layers of printed circuit board size, can make full use of the intermediate layer to set up shielding, a better realization of the proximity of grounding, and effectively reduce the parasitic inductance and shorten the length of the signal transmission, but also significantly reduce the signal cross-interference, etc., all of which are beneficial to the reliability of high-frequency circuitry.

2. High-speed electronic devices between the pins of the lead bends the less the better

High-frequency circuit wiring of the lead is best to use a straight line, the need to turn, available 45-degree fold or arc turn, this requirement in the low-frequency circuits are only used to improve the strength of the copper foil adhesion, while in the high-frequency circuits to meet this requirement can reduce the high-frequency signals to the outside of the launch and coupling between each other.

3. High-frequency circuit device pins between the lead the shorter the better

Signal radiation intensity is proportional to the length of the signal line, high-frequency signal leads the longer, the easier it is coupled to the components close to it, so for such signals as the clock, crystal, DDR data, LVDS lines, USB lines, HDMI lines, and other high-frequency signal lines are required as much as possible, the shorter the line, the better.

4. The fourth trick: high-frequency circuit device pins between the lead layer alternation the less the better!

The so-called “less alternation between the layers of the lead, the better” means that the components used in the connection process of the hole (Via) the less the better. According to the side, a hole can bring about 0.5pF of distributed capacitance, reduce the number of holes can significantly improve speed and reduce the possibility of data errors.

5. Pay attention to the signal line close to the parallel alignment of the introduction of “crosstalk”

High-frequency circuit wiring should pay attention to the signal lines in close proximity to the parallel alignment of the introduction of “crosstalk”, crosstalk refers to the coupling phenomenon between the signal lines are not directly connected. As high-frequency signals along the transmission line is transmitted in the form of electromagnetic waves, the signal line will play the role of the antenna, the energy of the electromagnetic field will be emitted around the transmission line, the signal due to the mutual coupling of the electromagnetic field and the resulting undesired noise signal is called crosstalk. parameters of the PCB board layer, the spacing of the signal line, the driving end and the receiving end of the electrical characteristics, as well as the signal line termination method of the crosstalk have a certain impact. So, in order to reduce the crosstalk of high-frequency signals Therefore, in order to reduce the crosstalk of high-frequency signals, it is required to do the following as much as possible when wiring:

Under the condition that the wiring space allows, insert a ground line or ground plane between two lines with serious crosstalk, which can play the role of isolation and reduce crosstalk. When the space around the signal line itself there is a time-varying electromagnetic field, if you can not avoid parallel distribution, parallel signal lines can be arranged on the opposite side of a large area of “ground” to significantly reduce the interference.

Under the premise of wiring space permits, increase the spacing between adjacent signal lines, reduce the parallel length of the signal lines, clock lines as perpendicular as possible with the key signal lines rather than parallel. If the parallel alignment within the same layer is almost unavoidable, in two adjacent layers, the direction of the alignment must be perpendicular to each other.

In digital circuits, the clock signal is usually a fast-edge signal, external crosstalk. Therefore, in the design, the clock line should be surrounded by ground wires and more ground holes to reduce the distribution capacitance, thereby reducing crosstalk. Clock on high-frequency signals try to use low-voltage differential clock signals and packet ground way, need to pay attention to the integrity of the packet ground hole punching.

Idle not used inputs do not hang, but will be grounded or connected to the power supply (power in the high-frequency signal loop is also the ground), because the suspended line may be equivalent to the transmitting antenna, grounding will be able to inhibit the emission. Practice has shown that this approach to eliminate crosstalk can sometimes be immediately effective.

6. IC block power supply pins to increase the high-frequency decoupling capacitance

Each integrated circuit block power supply pin near the increase of a high-frequency decoupling capacitance. Increase the power supply pin high-frequency decoupling capacitance, can effectively inhibit the power supply pin on the high-frequency harmonics form interference.

7. Isolation of high-frequency digital and analog signal ground lines

Analog ground, digital ground line to the public ground with high-frequency choke bead connection or direct isolation and choose a suitable place for single-point interconnection. High-frequency digital signal ground potential is generally inconsistent, there is often a certain voltage difference between the two directly; and, high-frequency digital signal ground is often with a very rich high-frequency signal harmonic components, when directly connected to the digital signal ground and analog signal ground, high-frequency signal harmonics will be coupled through the ground to the analog signal to interfere with the way.
In general, the high-frequency digital signal ground and analog signal ground is to do the isolation, can be used in the appropriate location of a single point of interconnection, or the use of high-frequency choke bead interconnection.

8. Avoid the formation of the loop alignment

Various types of high-frequency signal alignment try not to form a loop, if you can not avoid the loop area should be as small as possible.

9. Must ensure good signal impedance matching

Signal in the transmission process, when the impedance mismatch, the signal will occur in the transmission channel signal reflection, reflection will make the synthesized signal overshoot, resulting in the signal fluctuations in the vicinity of the logic threshold.
Eliminate the reflection of the fundamental approach is to make the transmission signal impedance is well-matched, due to the load impedance and the transmission line of the characteristic impedance of the larger the difference between the reflection of the larger, so should be as much as possible to make the signal transmission line of the characteristic impedance of the load impedance and load impedance is equal; at the same time, but also to pay attention to the PCB on the transmission line can not be a sudden change or corners, as far as possible to maintain the transmission line at all points of the impedance continuity, or in the transmission line between the various segments will be a reflection.

10. Maintain the integrity of the signal transmission

Maintain the integrity of the signal transmission, to prevent the “ground bounce phenomenon” caused by the division of the ground.

LST Technology participated in the Philippine Semiconductor and Electronics Show

10/30/2023 在： /通过：

On October 27, 2023, the 18th Philippine Electronics Exhibition (PSECE) ended successfully. As the largest and most authoritative electronic exhibition in the Philippines, merchants from countries from the United States, France, France, Germany, Japan, China, South Korea, etc. come to the exhibition. Enterprises including semiconductor manufacturing, consumer electronics, smart homes, PCB manufacturing, production equipment and other fields provide a variety of choices for the Philippines market.

As a PCB one -stop solution supplier, Shenzhen LST Technology has brought a variety of PACB samples and electronic manufacturing solutions to the audience. During the exhibition, we showed a series of high -performance, high -quality PCB circuit board products, including high -precision, high reliability, high integration PCB board, and customized solutions. We also introduced our product characteristics and technical advantages to visitors through brochure, display video and other methods.

Through the exhibition exchanges, let more customers know and understand LST, and we also know more clearly about market demand. We will adhere to the production concept of “efficient, transparent, high quality”, and provide high -quality design for global customers worldwide Production service.

Shenzhen LST Technology is a professional PCB manufacturing supplier. At the same time, we also provide a one -stop service of electronic manufacturing. Our service areas include smart homes, consumer electronics, new energy products, medical equipment, automotive accessories, etc. We welcome global customers to visit our company.

Introduction to PCB etching technology

10/23/2023 在： /通过：

PCB manufacturing requires a variety of processes, among which PCB etching is the most important link. Eclipse refers to the process of removing excess copper from the PCB light board, and the remaining PCB line diagram.

It sounds simple, but it contains a lot of complex craftsmanship. In order to help everyone better understand PCB etching technology, we deliberately prepare an operating guide for everyone to learn and discuss. The specific content is as follows.

What is PCB etching?

PCB etching is the process of removing unwanted copper from a printed circuit board. Once all of the excess copper has been removed from the PCB, only the required circuit remains.

Before the etching process begins, a layout for the board is generated. This desired layout for the board is transferred onto a PCB by a process called photolithography. This forms the blueprint that decides which pieces of copper must be removed from the board.

On the outer layer of the PCB, the tin plating acts as the etch resist. However, in the inner layer, the photoresist is the etch resist. Generally speaking, there are two approaches to inner layer and outer layer PCB etching. These are dry etching and wet etching. Here at ABL Circuits, we use a wet etching process using a Tech Win Alkali Etching Machine.

Wet PC B etching method

Wet etching is a etching process in which unwanted materials are dissolved when immersed in chemical solutions.

According to the erosion agent used, PCB manufacturer Tongyu adopts two wet etching methods:

1. Acid etching (iron chloride and copper chloride).

2. Alkaline etching (ammonia)

Acid etching process

The acidic method is used to etch the inner rigid PCB layer, which involves chemical solvents, such as iron chloride FECL3 or copper chloride (CUCI2). Compared to alkaline methods, acidic methods are more accurate, cheaper but more time-consuming. This method is suitable for the inner layer, because acid will not react with the photoresist, nor will it damage the required part. In addition, in this method, the bottom cut is the smallest.

The bottom cut is the horizontal corruption of the etching material below the most lead layer. When the solution encounters copper, it attacks copper and leaves a protected orbit. Use anti-corrosion electroplating or light shielding to protect the track. At the edge of the track, a certain amount of copper will always be removed below the resistance, which is called the bottom cut.

1. Copper etching

Copper chloride is the most widely used etching agent because it can accurately etch fewer characteristics. The ammonia process also provides a constant etching rate and continuous regeneration at a lower cost.

The maximum etching rate of the copper chloride system is a combination of copper hydride-sodium ammonia-HCI system. The combination provides a maximum turbid engraving rate of 55 seconds at 130 ° F. Therefore, this type of etching is used for the inner layer of etching the fine line

Note: The use of chlorine gas requires adequate ventilation, storage tanks and cylinders to store and leak detection equipment. In addition, it must be approved by the emergency agreement, personal protection equipment, trained operators, and the fire department.

2. Triscel oxide etching

Due to the high cost of copper etching agents, the use of iron chloride etching agents in industry is limited. However, iron chloride is an attractive spray etching because it is easy to use, the ability to maintain copper, and the ability to use it in rare batch applications. Iron chloride can be used with silk ink, lithography glue and gold pattern, but cannot be used with tin or tin/lead.

Generally, the iron chloride solution is dissolved in water, with a concentration range of 28-42% (by weight). HCI (5%) is also mixed with the solution to prevent the formation of insoluble hydroxide and iron oxide.

The iron chloride ratio is usually 36 BE, or about 4.0LB/Gal Feci3. The content (HCL) for commercial use is within 1.5 to 2%.

Alkaline etching process

Alkaline method is used to etch the PCB outer layer. Here, the chemicals used are copper chloride (CUCL2) ten hydrochloride (HCI)+hydrogen peroxide (H2O2)+water (H20) composition. The alkaline method is a fast process, and it is also a bit expensive. The parameters of this process must be carefully followed, because if you touch the solvents for a long time it will destroy the circuit board, the process must be well controlled.

The entire process is carried out in a high pressure air spray, and the PCB is exposed to the fresh etching spray. Some important parameters are required in the alkaline PCB etching. They are the amount of panel movement, chemical spray, and copper to be etched. This ensures that the etching process is completed uniformly through the straight end.

In the etching destruction, the points that are not required for copper etching are breakpoints. This is usually done from the midpoint of the atomicization chamber. For example, assuming the length of the atomization chamber is 2 meters, the breakpoint will be reached when the plate reaches the intermediate point.

PCB Etching Process

The PCB etching process must follow the following steps:

Step 1: The very first step of the etching process is designing the circuit, using the software of your choice. Once the design is ready, flip it, and then get it printed.

Step 2:On the transfer paper, print the circuit design. Make sure that the design is printed on the shiny side of the paper.

Step 3: Now, take the copper plate, and rub sand paper on it. This will make the surface of copper rough, and thus helps it to hold the design efficiently. There are certain points to remember step 3 till the last step:

Use safety gloves, while handling copper plate and etching solution. This will prevent the oil from hands getting transferred to copper plate, and will also protect your hands from the solution or chemicals.
When you are sanding the copper plate, make sure you do it properly especially at the edges of the plate.
Step 4: Now, wash the plate by some rubbing alcohol and water, so that any small particles of copper that get removed from the surface during sanding are washed off. Allow the plate to dry after washing.

Step 5: Cut the printed design properly, and place them on the copper plate facing down.

Step 6: The copper plate is now passed through the laminator several times until the plate gets heated.

Step 7: Take the plate out from the laminator, after it is hot, and hold it in a cold bath. Agitate the plate so that all the paper comes off and floats on the water. You will see a traced circuit in black on the copper plate.

Step 8: Now take the board out of the bath, and place it in the etching solution. Agitate the copper plate for around 30 minutes. Ensure that all the copper around the design is dissolved.

Step 9: Take out the copper plate and wash it in the water bath again. Keep it to dry. Once it has dried completely, you can use rubbing alcohol to remove the ink transferred to the printed circuit board.

Step 10: This completes the etching process of a printed circuit board. You can now drill the holes using proper tools with the required drill bit size.

About Us

LST Technology is a professional PCB and PCBA manufacturers. We provide one-stop production services for global customers. In 18 years, PCB manufacturing assembly experience. If you have PCB business needs, please leave a message to us. I will reply to you for a while.