ADG5401F Fault Protection SPST Switch Analog Devices Inc. ADG5401F Fault Protection SPST Switch features overvoltage protection, power-off protection, and overvoltage detection on the source pins (S and SFB). The ADG5401F has a protected secondary feedback channel for use with a digital-to-analog converter (DAC) or amplifier outputs. When no power supplies are present, the switch remains in the off condition, and the switch inputs are high impedance.