In the context of rapid development of electronic information technology, high-frequency circuit boards are widely used in 5G communications, radar systems, high-speed interconnection equipment and other fields. Compared with traditional circuit boards, high-frequency boards put forward higher requirements for signal integrity, impedance control, electromagnetic compatibility and other aspects. For PCBA processing companies, high-frequency board testing is not only more complex, but also on the test strategy, equipment capacity and personnel quality has also put forward a new challenge.
1、High-frequency Characteristics of The Test Challenges
high-frequency circuits is the core feature of high signal frequency, fast transmission rate, so its electrical properties by the subtle process error is greatly affected. Traditional PCBA processing, ICT and FCT and other standard test methods are difficult to accurately capture the signal integrity of high-frequency board. For example, minor alignment width deviations and improperly handled vias may lead to impedance discontinuities, signal reflections and other problems that are not apparent in low-frequency products. In addition, high-frequency signals are more susceptible to electromagnetic interference, the design and layout of the test environment also need to be more rigorous.
2、Test Equipment And Fixture Adaptation Requirements are Higher
high-frequency PCBA test on the test fixture and probe structure, materials put forward strict requirements. Traditional probes due to the presence of parasitic inductance and capacitance, may cause distortion in high-frequency signals. Therefore, it is necessary to use coaxial probes or microwave-grade interfaces with good high-frequency performance, and reasonable wiring in the test fixture to reduce the signal path. In addition, the test platform should have sufficient bandwidth and low noise performance, to avoid the introduction of interference in the test itself, affecting the accuracy of the judgement.
3、The Special Test Project is Indispensable
Compared with the conventional board test, high-frequency PCBA processing products should be more detailed in the test project settings. In addition to the basic power supply, electrical connection test, should be added to the impedance test, time domain reflection test (TDR), signal integrity analysis and other special projects. These tests can help confirm the continuity and transmission quality of the signal path and identify structural defects in advance that may lead to high-speed signal distortion. In the FCT stage, high-speed signal operation should also be simulated to verify the response capability of the entire system under high load.
4、High-frequency PCB Material Characteristics Need to be Included in The Test Considerations
High-frequency circuit boards often use PTFE, PPE and other high-frequency specialised materials, the processing performance of these materials is very different from ordinary FR4. For example, the material is less hygroscopic, different coefficients of thermal expansion, resulting in a narrower window for the welding process. The testing phase should pay attention to problems such as false soldering and cold soldering triggered by material properties, especially for tiny BGA devices and high-speed connector positions. At the same time, the impact of welding on high-frequency transmission performance should also be verified to ensure that the assembly process has not adversely affected the electrical performance.
5、Test And Design Need to Front Synergy
To enhance the effectiveness of high-frequency PCBA testing, testing strategy can not only in the finished product stage ‘remedy’, but should be involved in the product design stage of synergy. Design team in the wiring planning, should consider the rationality of the test point layout, test fixture interface compatibility and other factors, to provide the basic conditions for subsequent efficient testing. Especially in the microwave frequency band PCBA project, test point layout is unreasonable is likely to directly lead to the inability to test or test error is too large, affecting the overall delivery schedule.
The rise of high-frequency circuit boards has promoted the technological upgrading and capability expansion of the PCBA processing industry. In this process, testing as a key link to ensure quality, its importance is increasingly prominent. Only by deeply understanding the test challenges brought by high-frequency characteristics, configuring corresponding equipment, formulating exclusive programmes, and promoting the synergistic development of design and test, PCBA processing enterprises can stand firm in the wave of the high-frequency era and achieve higher levels of product delivery and customer satisfaction.
Choosing an experienced and fully qualified electronic EMS partner and investing sufficient resources in design review, process validation and rigorous testing is the key to ensuring successful mass production and long-term reliable operation of PCBA.
TORTAI Electronics serves more than 27 customers from all regions of the world and has received their unanimous praise. We ensure their full range of quality services, but also provide customers with DFM design for manufacturability programme, which can reduce the time and cost of product manufacturing, but also reduce the cost of product after-sales service. Meanwhile, TORTAI Electronics has a perfect after-sales and logistics team, so that the products get higher quality service tracking.