3-to-8 Decoder/Demultiplexer

The VHCT138A is an advanced high speed CMOS 3-to-8 DECODER 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. When the device is enabled, 3 Binary Select inputs (A0, A1 and A2) determine which one of the outputs (O#0-O#7) will go LOW. When enable input E3 is held LOW or either E#1 or E#2 is held HIGH, decoding function is inhibited and all outputs go HIGH. E3, E#1 and E#2 inputs are provided to ease cascade connection and for use as an address decoder for memory systems. Protection circuits ensure that 0V to 7V can be applied to the input pins without regard to the supply voltage and to the output pins with VCC = 0V. These circuits prevent device destruction due to mismatched supply and input/output voltages. This device can be used to interface 3V to 5V systems and two supply systems such as battery backup.