The demand for semiconductor Integrated Chips (IC's) is ever increasing and is driving an increase in demand for more precise and dense semiconductor test equipments like Automated Test Equipment (ATE). An ATE is a dense test equipment that houses various test boards, each capable of sourcing or measuring various types of digital test patterns, arbitrary waveforms, powerful DC voltage sources, current sources etc. High density in resource count and shrinking board dimension is key to enable higher test throughput.

For instance, one of the resource in an ATE is a Source Measurement Unit (SMU) instrument that can both source current/voltage and measure current/voltage. SMU resource combines the functionality of two instruments (programmable power source and digital multimeter) in one. Depending on the specifications, some SMU's can also be stacked in series as shown in Figure 2-7 to achieve higher test voltages demanded by semiconductor technologies that require higher bias voltages.

Functional isolators like ISO65xx provide the size advantage for space constrained applications, commonly seen in Test and Measurement cards. ISO65xx can be used between the central control ASIC and each SMU card. When multiple SMU cards are stacked, ISO65xx blocks high-voltage common without introducing leakage current across the barrier. Generally, each resource has a maximum voltage specification with respect to tester ground, which determines the functional isolator working voltage (V_IOWM) needed in the design.