1. I looked upon several Boundary Scan Test (BST) technologies currently used by the PCBA test
industry. Following are the list of BST testers and their capabilities.
1. Standalone BST Testers: These BST testers are connected to the Device Under Test (DUT)
only via JTAG port. It sends signals to the Boundary Scan (BSC) capable IC on the DUT to
drive its pins, and receives the logic states of those IC pins in the return signals. This tester can
detect the BSC IC pins 'short-circuit' faults, and the 'open-circuit' faults between BSC IC pins.
All other PCBA faults such as 'open-circuit' between IC pins and connection header are not
covered.
2. Integrated BST & Special BSC I/O chip : Augmenting the Standalone BST tester, this tester
use BST manufacturer special BSC I/O chip for testing with DUT. With the BSC I/O chip's
JTAG port connected in cascade with that of DUT BSC IC, the BSC I/O chip's pins can be
connected to other DUT test access points to perform additional test functions and enhance the
test coverage.
3. Integrated BST & ICT Tester : The ICT tester runs like current prevailing vectorless testers
except that DUT power is turned on due to the needs of BST. In their test operations together,
the 'open-circuit' faults between BSC IC pins and the other devices can be detected.
4. Integrated BST & Flying Probe Tester : With the advantage of precision probes placement, the
incorporation of Flying Probe Tester can add test coverage detecting 'open-circuit' faults
between BSC IC pins and Flying Probe access points.
5. Integrated BST & Digital ICT Tester : With Digital ICT tester connected to DUT test access
points around DUT BSC IC, this integrated tester can inter-work BST and digital test functions
directly, interactively, and system-wide parallel. They can detect DUT BSC IC 'short-circuit'
and 'open-circuit' faults between BSC IC pins and DUT test access points.