Thermal Imaging System for Circuit Board Troubleshooting
Many circuit board defects cannot be identified easily using conventional inspection and failure analysis methods such as in-circuit test, functional test, optical inspection, and X-ray inspection. Such defects include the following:
- Power-to-ground and low resistance shorts
- Stressed and marginal components
- Defective BGAs, VCOs, and decoupling capacitors
- Faulty heat sink attachment
Technicians and engineers can spend many hours debugging PCBs with such defects and these boards often end up in the scrap pile. The EL troubleshooting system provides an alternative method of fault detection using infrared temperature measurement and analysis that can isolate these defects, thus filling the gaps between conventional inspection and debugging techniques.
EL is an effective and economical tool that can reduce debugging costs and minimize scrap. When is used as the first screen of defective boards, EL can quickly provide useful troubleshooting information, dramatically reducing time to repair.
Troubleshooting Software Tools
- Model Board Comparison to troubleshoot more complex PCB and components defects
- Lock-in Thermography to locate short circuits
- Transparent picture overlay to locate defects on the board
Failure Modes Detected
- Interlayer, hidden, and resistive shorts
- Faulty components
- Stressed components
- Latent defects
- Heat sink and die attach problems
EL can also be used to inspect boards for basic functionality by comparing their temperature performance to a known good board. Although EL cannot provide the same detailed level of functional verification as a functional test, it can provide verification of basic board operation. Advantages of EL over traditional functional testers include low cost and fast setup. No custom hardware is required and tests can usually be setup in less than an hour. EL is ideal when the high cost of a dedicated functional tester cannot be justified.
Compliments Other PCB FA Tools
When used in conjunction with other failure analysis tools, EL can help speed up the diagnostic process. For example, EL can be used to significanlty reduce the defect search area before using analog signature analysis (ASA) to pinpoint the fail site.