Key facts
- Brand
- Philips
- Model
- HCT138
- Industry
- Industrial
- Documents
- 2
- Languages
- EN
- Last added
- 2012-07-02
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Philips 74HC/HCT138 3-to-8 Line Decoder/Demultiplexer Datasheet
The document describes the 74HC/HCT138 integrated circuit, which functions as a high-speed Si-gate CMOS device and is pin compatible with low power Schottky TTL. It features three binary weighted address inputs and provides eight mutually exclusive active LOW outputs when enabled.
Key characteristics include demultiplexing capability, multiple input enable for easy expansion into larger decoders (such as 1-of-32), and standard output capability. The datasheet details the pin configuration, logic symbols, functional diagrams, truth tables, and AC/DC performance parameters including propagation delay and transition times.
Philips HCT138 specifications
| Device Type | 3-to-8 line decoder/demultiplexer; inverting |
|---|---|
| Technology | high-speed Si-gate CMOS |
| Pin Compatibility | low power Schottky TTL (LSTTL) |
| Output Capability | standard |
| IC Category | MSI |
| Address Inputs | three binary weighted (Ao, A1, Az) |
| Outputs | 8 mutually exclusive active LOW (Yo to Y7) |
Source: Philips 74HC/HCT138 3-to-8 Line Decoder/Demultiplexer Datasheet
All Philips HCT138 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
Questions answered in these manuals
What is the function of the enable inputs?
The device features three enable inputs: two active LOW (E1 and E2) and one active HIGH (E3). Every output will be HIGH unless E1 and E2 are LOW and E3 is HIGH.
From: Philips 74HC/HCT138 3-to-8 Line Decoder/Demultiplexer Datasheet
Can the 74HC/HCT138 be used for memory chip select decoding?
Yes, it is described as ideal for this application due to its demultiplexing capability.
From: Philips 74HC/HCT138 3-to-8 Line Decoder/Demultiplexer Datasheet
What function does the Philips 74HC/HCT138 perform?
It is a 3‑to‑8 line decoder/demultiplexer with inverting (active‑LOW) outputs.
From: Philips 74HC/HCT138 3-to-8 Line Decoder/Demultiplexer Datasheet
How many address inputs does the 74HC/HCT138 have?
The device accepts three binary‑weighted address inputs (A0, A1, A2).
From: Philips 74HC/HCT138 3-to-8 Line Decoder/Demultiplexer Datasheet