How to choose patch inductor for PCBA foundry and material?

In PCBA fabrication and material substitution, the chip inductance plays the functions of choke, decoupling, filtering and tuning. There are two types of chip inductors: winding type and lamination type. How to choose chip inductors for PCBA production and material replacement?

PCBA foundry and material placement inductance selection knowledge

1. Universal inductors suitable for normal tens of megahertz circuits.

2. Most patch inductors can be welded by reflow welding and wave soldering, but some patch inductors cannot be welded by wave soldering.

3. The net width of the patch inductor should be less than the net width of the inductor, so as to avoid excessive solder and resulting in excessive tensile stress during cooling and changing the inductor value.

4. The precision of most patch inductors available on the market is ±10%, and the patch inductors with precision higher than ±5% need to be ordered in advance.

5. During maintenance, the patch inductance cannot be exchanged only depending on the inductance quantity. The task frequency band of the patch inductor should be clear to ensure the task function.

6. The shape and size of the patch inductor are basically similar, which cannot be easily identified from the shape. So in the manual welding or manual patch, be careful not to take the wrong parts.

7. At present, there are three kinds of common chip inductors: microwave high-frequency inductors suitable for frequency bands above 1GHz; Suitable for high frequency patch inductors in resonant circuits and frequency selective circuits.

8. Different commodities, the coil diameter is different, the opposite inductance, the DC resistance is not opposite. The DC resistance in high frequency circuit has great influence on Q value.

9. The high current allowed through is also a parameter of the patch inductance. When the circuit requires high current flow, the capacitance factor should be taken into account.

10 power inductance used in DC/DC converter when the inductance size will indirectly affect the state of the circuit, can be used to increase or decrease the method to change the inductance.

11. Wound inductors are generally used for communication equipment in the 150-900mhz frequency band. In the frequency circuit above 1GHz, it is necessary to choose the microwave high frequency inductor.

2. How do PCBA processing manufacturers correctly deal with humidity sensitive components?

PCBA processing manufacturers sometimes encounter some special components in patch processing, such as MSD, which is also moisture sensitive components, referred to as humidity sensitive components, which are susceptible to the influence of ambient temperature, humidity and static electricity. The impact of humidity sensitive components on SMT processing is no less than ESD. It is necessary to strengthen the storage and use management of humidity sensitive components in SMT processing.

PCBA manufacturers can standardize the MSD process control method, so as to avoid the component damage caused by humidity sensitive components in the process of reflow welding, reduce the resulting product defect rate, and improve the reliability of products.

In actual processing, MSDS that are damp are generally baked according to the baking conditions in the warning label on the original packaging bag of the manufacturer. For components manufacturers do not have corresponding requirements, it is recommended to use high temperature baking method. During the replacement of the MSD carrier, pay attention to prevent ESD damage to the components. Low temperature baking conditions are not recommended for general MSD baking.

PCBA processing moisture sensitive devices use precautions

1. Ovens used for baking should be ventilated and able to maintain the required temperature under humidity of less than 5%.

2. SMT patch components shipped in high temperature carriers can be baked at 125℃ unless otherwise stated by the manufacturer.

3. SMT patch components transported in low-temperature carrier shall not be baked at a temperature higher than 40℃. If higher temperature baking is used, the low temperature carrier should be removed and replaced with a high temperature resistant carrier.

4. The paper or plastic carrier should be evacuated before baking, and the rubber belt or plastic tray should also be evacuated when baking at 125℃.

kingford specializes in providing overall PCBA electronic manufacturing services, including upstream electronic component procurement to PCB production and processing, SMT patches, DIP plug-ins, PCBA testing, finished product assembly and other one-stop services.

The company gives full play to its competitive advantages in scale procurement and quality control, and has signed long-term cooperation agreements with many electronic component manufacturers at home and abroad and around the world to ensure the quality and stable supply of raw materials, and transfer the benefits to customers.