Flying Probe Test Ideal For Prototypes

The new generation of flying probes stem from new and innovative ideas aimed at providing increased test speed, improved access, and greater fault coverage.

Flying probe test development is a cost effective method and technique for providing a methodology for prototype verification. Unlike ICT, no costly test fixtures are needed. This eliminates enormous cost programming time and allows design changes with simple test program changes. Flying probes allow connection to test points and camera use for visual inspection. Flying probe test is also capable of doing some power up testing by injecting signals at certain points on the board and detecting the output at other locations.

Flying probes can access component pins directly or through automated test point probing without requiring test points, the improved test coverage over in-circuit tests that use beds-of-nails. It uses the vias on the board as embedded test points to be utilized as test points, thereby curtailing the need for test points.

This feature is valuable in handheld and mobile devices because board real estate is a precious commodity, which is used extremely carefully. Eliminating some, if not all the test points saves considerable amounts of board real estate.

Flying probe testing is a method for low-volume and for prototype circuit boards due to its ease of use in programming even in today’s era of increasing complexity and density. Low-volume production runs or prototypes do not normally justify the cost of bed-of-nails in-circuit testing, where fixtures are expensive. The use of flying probe technology provides a cost-effective solution.

Flying probe offers OEM customers the following benefits:

  • No extra cost for making the fixtures as required in ICT.
  • Programming time is very minimal, a couple to few days so customers can quickly check their designs.
  • Quick and easy way to test the prototype and proof of concept for their design and help with time to market.
  • Easy way to detect shorts, opens, missing components, wrong value components, wrong polarities, thereby cutting the debug time for customers
  • Easy change over from one revision of the board to another while it is in prototyping stage where all the debugs are all not complete and customers are making changes on the fly.
  • A quick way to test the product while the comprehensive ICT is developed, which takes a couple to few months for a new development.
  • Debug time for customers is cut in half or more after flying probe is done because this test already detects most manufacturing defects.
  • No extra DFM or data messaging efforts are required for flying probe, reducing the testing time for OEM customers.

Other Notes:

Most flying probe testers conduct signal integrity testing on populated boards, test open pins on ICs, and measure resistor and capacitor values, as well as check for shorts and opens on inductors, diodes, MOSFETs, relays, and transformers.

Flying probe can be performed without an expensive fixture, as mentioned above. Four to eight test heads move across the PCB under test at high speed. Electrical probes located on each head make contact and test device vias and leads on the board to provide sequential access to the test points. These probes are electro-mechanically controlled and move as precisely as within a few mils. Flying probe testers are categorized as an in-circuit test (ICT) system or manufacturing defects analyzer (MDA).

Flying probe is often used to validate line set-up without the cost and cycle time related to designing and building traditional bed-of-nails fixtures. Hence, flying probe can provide fast turn-around and high fault coverage benefits, but without the test fixture cost, which can sometimes run into outrageously high numbers.