Custom pin electronics for VLSI automatic test equipment

Today´s modern VLSI `tester-per-pin´ architecture test systems provide a high degree of flexibility in testing a wide range of VLSI devices. However, even with this flexibility in tester resources, there will always be some devices that will require an additional incremental test capability that was not designed into the test system. The author describes a concept that involves customized tester pin electronics requiring virtually no commitment from the test system resources other than power and ground. The key feature of the custom pin card is that it does not require any tester resource boards dedicated to controlling its function as a pin card. Also, the custom pin card does not require any type of operating system software for control. The only software required is that which resides in the device test program. An added feature of the custom pin card is achieved by removing the customized circuitry from the load board and placing it inside the test head. The test solution becomes inherently more reliable and maintainable because the circuitry resides in a more stable and controllable environment. Results on a high-speed clock pin card and a high-voltage buffer pin card are presented