There are two important fixturing considerations for the Connect Check test method. It is important that you understand these two considerations throughout the test and fixture development process. They are:
- the return path for the response pin reference voltage (see Reference Voltage Return)
- guarding
fixed
nodes (see Guarding Fixed Nodes)
Reference Voltage Return
As shown in Figure 3, the fixture generation software assigns probes and wires to connect the reference voltage return on the mux+ref card to a location on the ground node of the board under test. During test development, you need to add reference voltage return wires for any devices to be tested with Connect Check that are not connected to the board ground node. During debug you might need to change the location of the probe on the board ground node.
Figure 3 Reference voltage ground
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