Cost/Coverage Tradeoffs
Comparison of ICT, AXI & AOI
http://www.radio-electronics.com/info/t_and_m/ate/automated-x-ray-inspection-pcb-bga.php
With JTAG too
http://www.emasiamag.com/article-3251-completefaultcoveragethroughthecombinationoftesttechnologies-Asia.phpl
What kind of test is best for me and my budget?
The figure below illustrates the capabilities and limitations of Datest’s featured test platforms, arranged from least expensive to most expensive from an NRE standpoint. These are generalizations, and the graphic is presented as a way to reduce some misconceptions about the uses of each platform.
Ultimately the old adage applies that each customer's design, application, and circumstances are different. The Bottom Line is that Datest will work with you to achieve the optimal test solution for your needs and your budget.
Notes:
1. JTAG requires that the tested components be either Boundary Scan
or interconnected via Boundary Scan.
2. Toe of solder joint only
3. Powered components may not be included.
4. Requires vectorless test capability.
Below are guidelines listing cost/benefit tradeoffs of the various Datest platforms (“Plus and Minus of Test”) and a brief argument in favor of integrating multiple platforms (“So you think you cannot test your PCB?”) which, coincidentally, is Datest’s specialty. Also included below are guidelines for the use of Nodal Impedance Testing (NZT—used with the SPEA 4040 flying probe) and boundary scan testing, both of which enhance testability on suitably prepared designs.
Uses and Advantages of Boundary Scan Testing
Uses and Advantages of NZT with Flying Probe Testing
What is Scanworks and Why Do I Need It
Plus and Minus of Test
So You Think You Cannot Test Your PCB
How can I make my designs more testable?
This is a complicated question because one set of guidelines does not fit all platforms and every board design is different from the standpoints of packaging density, layer count, speed, and most notably, application. Nevertheless some generic observations, based upon experience, can be useful as a starting point toward the goal of achieving a (largely) testable board. With that background, we have attached mechanical testability guidelines from two of Datest’s fixture vendors as well as Testability Rules of Thumb used internally at Datest (As collated by Matt Turpin, Datest Sr. Test Engineer and frustrated Gag Writer). Also attached, with permission, are excerpts from SMTA/TMAG TP-101D (“Testability Guideline”), which provide a comprehensive set of electrical testability guidelines for all the major test platforms Datest uses. A link to the SMTA bookstore website is also attached should you wish to purchase the complete TP-101D guidelines.
ICT Testability In A Perfect World (PDF Download)
Mechanical DFT Guidelines Fixture Vendor 1 (PDF Download)
Mechanical DFT Guidelines Fixture Vendor 2 (PDF Download)
http://www.smta.org/store/book_store.cfm
