MC74VHCT138A

The MC74VHCT138A is an advanced high speed CMOS 3to8 decoder fabricated with silicon gate CMOS technology. It achieves high speed operation similar to equivalent Bipolar Schottky TTL while maintaining CMOS low power dissipation.

When MC74VHCT138A is enabled, three Binary Select inputs (A0 A2) determine which one of the outputs (Y0 Y7) will go Low. When enable input E3 is held Low or either E2 or E1 is held High, decoding function of MC74VHCT138A is inhibited and all outputs go high. E3, E2, and E1 inputs are provided to ease cascade connection and for use as an address decoder for memory systems.

The VHCT inputs are compatible with TTL levels. MC74VHCT138A can be used as a level converter for interfacing 3.3V to 5.0V, because they have full 5V CMOS level output swings.

The VHCT138A input structures provide protection when voltages between 0V and 5.5V are applied, regardless of the supply voltage. The
output structures of MC74VHCT138A also provide protection when V_CC = 0V. These input and output structures help prevent device destruction caused by supply voltage input/output voltage mismatch, battery backup, hot insertion, etc.