Boundary Scan

What Does Boundary Scan Mean?

A boundary scan is a testing standard which helps in defining the architecture and the techniques for solving hardware
issues related to components such as printed circuit boards (PCBs) and integrated circuits. Traditional
in-circuit testers are not well suited to testing highly complex and dense PCBs.
Short test times, increased diagnostic capability, higher test coverage and
lower capital device cost are some of the potential benefits from the use of
a boundary scan.


Techopedia Explains Boundary Scan

Development of surface-mounted packaging, development of multi-layer board to accommodate extra interconnects and miniaturization of device packaging were some of the factors leading to the development of boundary scan technology. It was developed as a long-term solution for circuit testing. A boundary scan can determine if each device is inserted properly and soldered onto the PCB or IC with the help of the dedicated test logic built into modern integrated circuits.

Microprocessors, telecom encoders, bus logic, bridges, DSPs and many others make use of boundary scan technology. Intel, Xilinx, Freescale, Broadcom and Analog are some of the device manufacturers which have embraced the boundary scan technology. Devices which are enabled with boundary scan make use of four to five dedicated test access port signals such as test mode select, test data in, test data out, test clock and test logic reset. The data captured from the signals is compared with expected results and necessary actions are then initiated.

Boundary scan significantly reduces production and development costs. With the help of automation, it can speed the test development and can improve the product quality with better fault coverage. One of the biggest benefits from the use of boundary scan is the ability to transform extremely tough printed circuit board testing issues into well-structured ones, which can then besolved with the help of software applications. Smaller companies which cannot afford costly in-circuit testers typically use boundary scan.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.