For systems that are sensitive during a start-up sequence, the active low
operation of the fault flags allow the system to ensure that the ADG5248F is
powered on and that all input voltages are within normal operating range before
initiating operation. The FF pin introduces a means to diagnose systems in
fault programmatically and can be used to stop long or expensive tests if a
The fault flags also offer more intelligence to the system, preventing
differential signals that over-voltage on both channels (e.g. ADG5249F dual 4:1
Mux)) presenting as “normal” operation.
The specific fault pin allows the user to debug which input channel is in fault
and can help with system debug (e.g. deciding which input sensor isn’t working
and needs to be replaced). The system can use this information to skip
over faulty channels and continue measurements on other channels which aren’t
in fault, rather than collecting faulty measurement data.