Boundary Scan Test

The boundary scan test is used to check PCB assemblies for interconnect faults. This test is also used to detect IC pin defects and analyze the core logic of IC devices.

Venture performs boundary scan tests on complex circuit boards that support the JTAG standard. These boards also incorporate IC packages such as processors, programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs).

To conduct the test, a boundary scan tool is connected to the TAP or the test access port, and scan cells are used to send testing data to the device being checked. These cells override individual pin functions, isolating each for the testing process.

Boundary Scan Test Instructions

Advanced boundary scan test software uses instruction sets to read board traces or device pins. Based on the test results, any interconnect faults and pin defects are quickly identified. These may include:

• Shorts
• Opens
• IC pin faults
• Missing pull resistors

Depending on the specific set of boundary scan instructions, the testing expert also checks the core logic of the device. This is done via the JTAG interface or testing ports and the scan data relayed by the BS cells.

No mechanical probes are required when conducting the boundary scan interconnect test. Instead, a series of test points called TAPs are used. These allow testing experts to input the required test data sets and are conveniently located on the board edges.

Advantages of Boundary Scan Testing

The boundary scan test can help detect both board functionality flaws and physical interconnection defects. By using this test, Venture ensures these benefits for your PCBA project.

• Reduced Costs: with no need for physical access, the boundary scan testing process costs less to perform, unlike other tests that would require fixtures and physical probes.

• Minimized Risk of Damage: the BS test does away with using mechanical tools to test smaller components. Instead, it integrates the test logic into the integrated circuit. This reduces the risk of damage.

• Reusable Test: The boundary scan test software allows for repeatability of the process, with testing patterns that can be reused. As a result, time and costs savings are realized.

• Increased Reliability: the boundary scan test is a powerful tool that provides high-precision results when testing a PCBA for both functionality and physical flaws.

• Reduced Test Time: the BS test is a fast process that reduces the time it takes to test your prototypes or finished boards. That translates to improved time to market for your product.

Boundary Scan Methods at Venture

To ensure the interconnections of your printed circuit boards are faultless, Venture uses these boundary scan methods: Connection test in JTAG-supported devices and JTAG to non-JTAG test.

• In the boundary scan connection test, PCBA connections are checked against those in the original board design. This is done by comparing them with the design’s netlist.
• The non-JTAG test aims to establish if devices that are not JTAG-compatible work as they should. These devices are accessible via the JTAG route and include DDR, SDRAM, SRAM, and ADCs.

The boundary scan test is used on densely packed circuits and assembled with complex IC components. It offers a safe and faster way of checking assembled PCBs without mechanical probes.

At Venture, we perform the boundary scan test using advanced software and testing equipment. This serves to ensure reliable test results and higher product quality. For any inquiries concerning our PCB and PCBA services, contact us now.