Importance of online testing ICT in PCB design

Despite the continuous development of competitive testing technology, online testing (ICT) is still one of the effective methods to test PCB components. The lasting appeal of ICT comes from the testing speed, usually only a few seconds. In addition, the test is accurate, and component-level error detection speeds up the diagnosis process and reduces the proficiency of diagnosis. This paper discusses the importance of online testing in PCB design.
What is online testing?
ICT needs a special automatic test equipment (ATE) to perform manufacturing defect analysis (MDA). It tests each component on the PCB separately. In addition, it also verifies such things as basic supply voltage measurement, diode and transistor directions, and passive component measurement (resistors and capacitors). It looks for open and short circuit faults.
Why is PCB design important?
In order to realize ICT, people need to invest in a bunch of nail test fixtures and a special test program. The total cost of these testing projects exceeds $12,000. Because of the high result of this NRE, this method is suitable for large capacity and stable design.
How to design PCB layout?
In order to make full use of the test strategy, the following points should be considered when designing PCB assembly layout:
Test board access: the electrical network with “unconnected” (i.e. unconnected IC pins) should have PCB design test board. An exception to the traditional “through hole” technology is that component legs on the welding surface of components can be inspected. Ideally, the pad diameter should be 0.05 inch, and the distance between the pad and other components should be at least 0.1 inch. This allows the use of robust test pins. In addition, the pad is at least 0.125 inches away from the PCB edge.
Design stability: It is important before determining whether the design is stable, because these devices can be very expensive.
Testing: Ideally, the test pad should be located on the soldering surface of PCB. The discussion between the two sides is feasible. If needle tip detection is required, wiring and additional transmission probes will make the lamp expensive.
Welding surface: Unless it is unavoidable, there must be no parts on the welding surface.
Tool holes: Be sure to add tool holes on the main PCB. These tool holes enable the tool pins to position the PCB in the fixture. These holes are 3 to 4 mm in diameter and are not plated. They should be located at the opposite corners of the diagonal with a clear space of about 5mm around them, so that the jig tool pins will not short-circuit the rails or components. Shenzhen SMT chip processing: The above is about the importance of online testing ICT in PCB design.