An In-Circuit Test Fixture That is Easy to Debug and Can Perform ISP
Many aspects are taken into consideration during the in-circuit test fixture design process. Factors such as: ease of debug, in-system programming, and power-up testing were the main considerations of this fixture design, which was manufactured for an automotive application. The in-circuit test program and fixture were developed for Acculogic’s iCT7000 in-circuit tester. One of the unique features of this fixture is the vacuum slide, which allows access to the probes when the vacuum is actuated. So, the top side of the fixture can be opened up while the probes are in contact with the units under test (UUT), thereby making it easier to debug the fixture. Another aspect of this fixture is that it allows the UUTs to be programmed after successfully completing the in-circuit test stage. This is achieved using an in-system programmer, which is installed inside the fixture and is capable of gang programming of up to 8 devices. A multi-latching relay card is incorporated in to the fixture, which further extends the functionality of the fixture. Using this device, a UUT can be selected to be powered-up. In addition, a marker probe – controlled by the relay card – marks any board that successfully passes in-circuit test and the programming stages. A final note. The tester’s fixture (electronic) interface connects horizontally with the fixture. This allows a more compact test fixture to be built, which means a lower fixture cost.