Texas Instruments develops a failsafe dual 2:1 multiplexer with latch immunity and 1.8V logic

     The Texas Instruments TMUX7436F is a CMOS analog multiplexer with dual channel 2:1 latched immunity. The device works well with dual power supplies (±5V to ±22V), single power supplies (8V to 44V), or asymmetric power supplies such as VDD = 12V, VSS = -5V.

     Providing overvoltage protection under on-power and off-power conditions makes the device ideal for applications where the power sequence may not be accurately controlled. In the case of power and power failure, the device can shield the maximum fault voltage of +60V or -60 V relative to ground. When there is no power supply, regardless of the switching input condition, the switching channel remains OFF and any control signals on the logical pins are ignored.

     If the signal path input voltage on any Sx pin exceeds the supply voltage (VDD or VSS) through the threshold voltage (VT), the channel is closed and the Sx pin becomes a high impedance. According to the DR Control logic, the leaky pin (Dx) is either pulled beyond the failure supply voltage or left in the float position.

     The device provides two active-low interrupt flags (FF and SF) to give fault details and support system diagnosis. The FF flag indicates whether any source input has encountered a failure condition, while the SF flag decodes which specific inputs have encountered a failure condition.