The VHC138 is an advanced high speed CMOS 3-to-8 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. When the device is enabled, 3 binary select inputs (A0, A1 and A2) determine which one of the outputs (O0-O7) will go LOW. When enable input E3 is held LOW or either E1 or E2 is held HIGH, decoding function is inhibited and all outputs go HIGH. E3, E1 and E2 inputs are provided to ease cas- cade connection and for use as an address decoder for memory systems. 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.
The 74VHC138 is a high‑speed CMOS 3‑to‑8 decoder/demultiplexer with low power dissipation and high noise immunity. It operates with three binary select inputs and three enable inputs, providing eight mutually exclusive outputs. The device is compatible with the standard 74HC138 pinout and can be used for address decoding in memory systems.
The datasheet includes electrical characteristics, absolute maximum ratings, recommended operating conditions, package options (SOIC, SOP, TSSOP, PDIP), and physical dimensions. It also contains ordering codes and a life‑support policy disclaimer.
| Typical propagation delay (fPP) | 5.7 ns |
|---|---|
| Supply voltage (recommended operating range) | 2.0 V to 5.5 V |
| Operating temperature range | -40 °C to 185 °C |
| Pin compatibility | Compatible with 74HC138 |
The typical propagation delay is 5.7 ns.
The recommended operating supply voltage is 2.0 V to 5.5 V.