MC74VHCT139A

The MC74VHCT139A is an advanced high speed CMOS 2−to−4 decoder/demultiplexer fabricated with silicon gate CMOS technology. It achieves high speed operation similar to equivalent Bipolar Schottky TTL devices while maintaining CMOS low power dissipation.

When MC74VHCT139A is enabled (E = low), it can be used for gating or as a data input for demultiplexing operations. When the enable input is held high, all four outputs are fixed high, independent of other inputs. The internal circuit of MC74VHCT139A is composed of three stages, including a buffer output which provides high noise immunity and stable output.

MC74VHCT139A output is compatible with TTL−type input thresholds and the output has a full 5.0 V CMOS level output swing. The input protection circuitry on this device allows overvoltage tolerance on the input, allowing MC74VHCT139A to be used as a logic−level translator from 3.0 V CMOS logic to 5.0 V CMOS logic, or from 1.8 V CMOS logic to 3.0 V CMOS logic while operating at the high−voltage power supply

The MC74VHCT139A input structure provides protection when voltages up to 7.0 V are applied, regardless of the supply voltage. MC74VHCT139A allows the MC74VHCT139A to be used to interface 5.0 V circuits to 3.0 V circuits. The output structures also provide protection when V_CC = 0 V. These input and output structures help prevent MC74VHCT139A destruction caused by supply voltage−input/output voltage mismatch, battery backup, hot insertion, etc.