The ST pin is an open drain output that should be pulled up to an external voltage for proper operation. When the TPS2117 is powering the output using VIN1, the ST pin will be pulled high by the external voltage source. Even if the device is blocking reverse current from VOUT to VIN1, selection of VIN1 will keep the ST pin pulled high. When the TPS2117 is powering the output using VIN2 or both channels are disabled, the ST pin will be pulled low. During thermal shutdown, the ST pin will be pulled low regardless of the channel being used.