PCBA Tech - How to choose PCBA electronic components correctly?

Many friends who do electronic processing will face the problem of purchasing PCBA electronic components. If you are just a R&D team or purchasers who do not understand processing, you will really have a headache when choosing electronic components. Today, I will give you a popular science on how to choose. To purchase electronic components, if you don't want to have trouble, you can directly find a PCBA factory for proofing PCBA, including labor and materials, one-stop electronic processing, assembly and shipment.

1. The importance of PCBA electronic component selection

The size, product model, and basic parameters of each electronic component are marked on the circuit diagram, which is the basis for the selection of electronic components. For the products that have been formed, the electronic components marked on the schematic circuit diagram are put into PCBA production and processing after design, research and development, and each basic parameter is confirmed according to the method of "qualitative analysis, quantitative estimation, and experimental adjustment". Under normal circumstances, whether the electronic components used are allowed to be replaced or not. However, for electronic equipment developers, amateur enthusiasts, and maintenance workers, due to the influence of many factors such as objective reasons, electronic components can also be used flexibly and flexibly under the conditions of compliance with technical specifications and standards due to the small amount of use.

In some special situations, even if you have a schematic diagram of the circuit, some electronic components are marked with incomplete basic parameters, such as electrolytic capacitors that only mark the capacity and not the breakdown voltage, so they must be reconsidered in the power circuit; commodity application field conditions and technical data If you don’t meet the requirements, you can change part of the electronic components to integrate them into reality; if an electronic component is difficult to buy locally, you can choose an electronic component that meets the standard to substitute; if an electronic component is found to be unreasonable during the maintenance process, you must replace it with a suitable one Of electronic components.

PCBA electronic components are circuit basic units that perform predetermined functions without being detachable and refined, such as resistors, semiconductor discrete components, semiconductor integrated circuit chips, microwave electronic components, magnetic electronic components, control switches, electrical connectors, and filters Devices, temperature sensors, fiber optic components, etc. Practice has proved that in electronic products, 44% to 67% of the total failure of electronic components is caused by improper selection, and the failure rate caused by the quality of the electronic components accounts for 33% to 46%. Therefore, the selection of electronic components occupies a key position in circuit design, and the design staff must attach great importance to it.

Second, the selection criteria of electronic components

1. Choose standard electronic components from PCBA manufacturers that have proven to have stable quality, high credibility, development prospects, and good reputation through practice. Obsolete or fake electronic components should not be used.

2. The technical characteristics, quality level, and application conditions of electronic components should meet the requirements of the design circuit.

3. In the case of meeting the performance indicators, electronic components with low power consumption, low thermal resistance, low loss, high power gain, and high efficiency should be selected.

4. Selection of domestic electronic components. It is preferable to select electronic components that have been certified and identified in compliance with international standards; electronic components that have been honed in application and that can meet the requirements and can be delivered stably; and other electronic components that have successful use experience and meet the requirements.

5. Imported electronic components. Electronic components in the PPL (selected product list) and QPL (qualified product list) of overseas authoritative departments; high-reliability electronic components that have been rigorously screened during processing; high-quality that has passed the domestic application evaluation and meets the requirements Of electronic components.

6. The selection should be based on the principles of standardization and generalization.

Three, the selection of electronic components

Electronic components are preferred, and the preferred practical manual of the product or the preferred product list (PPL) issued by the overseas authority should be applied. Design staff should formulate precise and clear technical specifications for purchasing electronic components. In order to ensure credibility requirements, the specifications should establish countermeasures and methods for screening (including re-screening) and quality consistency inspection. At the same time, a qualified electronic component purchase order should be drawn up according to the model specifications.

The factors that affect the credibility and quality of electronic components must be specified in the purchase order, such as quality level, environmental conditions, failure rate, technical specifications, packaging type, precautions (anti-static characteristics, integrated ic protection processing technology, etc.), Production suppliers, etc. Procurement specifications shall be implemented after being reviewed according to regulations. After the use of PCBA electronic components in the product is clear, its credibility should be estimated, and it should be considered whether it meets the credibility standard of the circuit to the electronic components.