Overview
The SN74HCT138N is a 3-line to 8-line decoder/demultiplexer produced by Texas Instruments. This device is part of the HCT series, known for its high-performance and compatibility with TTL (Transistor-Transistor Logic) voltage levels. It is designed for high-speed memory-decoding and data-routing applications, where short propagation delay times are crucial. The SN74HCT138N features three enable inputs, two of which are active-low and one active-high, simplifying cascading and data reception in complex systems.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (VCC) | 4.5 | 5 | 5.5 | V |
| Operating Temperature | -40 | 85 | °C | |
| Propagation Delay (tpd) | 23 | 36 | 54 | ns |
| Output Drive at 5 V | ±4 mA | mA | ||
| Input Current | 1 µA | µA | ||
| Supply Current (ICC) | 80 µA | µA | ||
| Number of Bits | 8 | |||
| Number of Terminals | 16 | |||
| Package Type | PDIP-16 |
Key Features
- Operating voltage range of 4.5 V to 5.5 V
- Outputs can drive up to 10 LSTTL loads
- Low power consumption, with a maximum supply current of 80 µA
- Typical propagation delay of 17 ns at 5 V
- ±4-mA output drive at 5 V
- Low input current of 1 µA max
- Inputs are TTL-voltage compatible
- Designed specifically for high-speed memory decoders and data transmission systems
- Three enable inputs (two active-low and one active-high) to simplify cascading and/or data reception
Applications
The SN74HCT138N is ideal for high-performance memory-decoding and data-routing applications. It is particularly useful in systems requiring very short propagation delay times, such as:
- High-speed memory systems
- Data transmission systems
- Cascaded decoder applications
- Demultiplexing applications
Q & A
- What is the operating voltage range of the SN74HCT138N?
The operating voltage range is from 4.5 V to 5.5 V.
- How many LSTTL loads can the outputs of the SN74HCT138N drive?
The outputs can drive up to 10 LSTTL loads.
- What is the typical propagation delay of the SN74HCT138N at 5 V?
The typical propagation delay is 17 ns at 5 V.
- What is the maximum supply current of the SN74HCT138N?
The maximum supply current is 80 µA.
- Are the inputs of the SN74HCT138N TTL-voltage compatible?
- How many enable inputs does the SN74HCT138N have?
- What is the package type of the SN74HCT138N?
The package type is PDIP-16.
- What is the operating temperature range of the SN74HCT138N?
The operating temperature range is from -40°C to 85°C.
- Is the SN74HCT138N RoHS compliant?
- What are some common applications of the SN74HCT138N?
