The STG5123 is a high-speed CMOS low voltage single analog SPDT (single-pole dual-throw) switch or 2:1 multiplexer/demultiplexer switch fabricated using silicon gate C2MOS technology. Designed to operate from 1.65 to 4.5 V, this device is ideal for portable applications. The device offers very low ON resistance (1 ) at VCC = 4.5 V. The switch S1 is ON (connected to common ports Dn) when the SEL input is held high and OFF (state of high impedance state exists between the two ports) when SEL is held low. The switch S2 is ON (connected to common port D) when the SEL input is held low and OFF (state of high impedance state exists between the two ports) when SEL is held high. Additional key features are fast switching speed, break-before-make delay time and ultra low power consumption. All inputs and outputs are equipped with protection circuits against static discharge, giving them ESD and transient excess voltage immunity.