Issues and Challenges of Testing Modern Low Voltage Devices with Conventional In-Circuit Testers

The popularity of low voltage technologies has grown significantly over the last decade as semiconductor device manufacturers have moved to satisfy market demands for more powerful products, smaller packaging, and longer battery life. By shrinking the size of the features they etch into semiconductor dice, IC manufacturers achieve lower costs, while improving speed and building in more functionality. However, this move toward smaller features has lead to lower breakdown voltages and increased opportunities for component overstress and false failures during in-circuit test. The chief reason is that testers designed for boards that traditionally operated with a power supply voltage of 5V are still being used on new generation ICs, which operate on 2.5V, 1.5V, or even 0.8V. These traditional in-circuit testers often do not have the accuracy, safety, and reliability features that are required to test low voltage technologies. This paper discusses the challenges of performing powered-up vector testing of low voltage technologies on traditional in-circuit testers and describes the safeguards that are necessary to ensure that test vectors do not violate the increasingly tight specifications of low voltage parts. It also describes the in-circuit test features that are most important for testing low voltage technologies: independently programmable, high accuracy driver/sensors; real time dynamic backdrive current measurement, programmable backdrive control, specialized digital controller; and multiple level digital isolation