The VHC139 is an advanced high speed CMOS Dual 2-to-4 Decoder/Demultiplexer fabricated with silicon gate CMOS technology. It achieves the high speed operation similar to equivalent Bipolar Schottky TTL while maintaining the CMOS low power dissipation. The active LOW enable input can be used for gating or it can be used as a data input for demultiplexing applications. When the enable input is held HIGH, all four outputs are fixed at a HIGH logic level independent of the other inputs. An input protection circuit ensures that 0V to 7V can be applied to the input pins without regard to the supply voltage. This device can be used to interface 5V to 3V systems and two supply systems such as battery back up. This circuit prevents device destruction due to mismatched supply and input voltages.