I have a small DAC that uses the UDA1352 audio DAC ic. Right now I just have a switch between the coaxial and toslink input to select which one to use. I would like to add a circuit that would automatically select which input is connected. The UDA1352 has a LOCK pin that goes high when PCM data is detected. My thought was to use the Lock into a circuit that would toggle high and low, into a analog switch IC. When the Lock pin was enacted, the circuit would hold the output either high or low. That would keep the input on. Not sure if I explained this right. Is there such a integrated circuit that will work like this?