Overview
The SN74AHC138DG4 is a 3-line to 8-line decoder/demultiplexer integrated circuit produced by Texas Instruments. This device is designed for high-performance memory-decoding and data-routing applications that require very short propagation-delay times. It is part of the 74AHC series, known for its advanced high-speed CMOS logic.
The SN74AHC138DG4 features three binary input lines (A, B, and C) that select one of eight output lines. The device includes three enable inputs, with two active-low and one active-high enable, which simplify cascading and data reception. This configuration allows for efficient implementation in various digital systems without the need for external gates or inverters.
Key Specifications
| Parameter | Min | Max | Unit |
|---|---|---|---|
| VCC Supply Voltage | 2 | 5.5 | V |
| Operating Temperature | -40 | 85 | °C |
| Input Voltage Range | -0.5 | 7 | V |
| Output Voltage Range | -0.5 | VCC + 0.5 | V |
| Continuous Output Current | -25 | 25 | mA |
| Propagation Delay Time (CL = 15pF) | 5.7 | 9.5 | ns |
| Package Type | 16-SOIC (0.154", 3.90mm Width) | ||
Key Features
- Operating voltage range: 2V to 5.5V
- Designed for high-speed memory decoders and data-transmission systems
- Three enable inputs to simplify cascading and/or data reception
- Latch-up performance exceeds 250mA per JESD 17
- ESD protection exceeds JESD 22: 2000V Human-Body Model, 1000V Charged-Device Model
- Three binary inputs to select one of eight active-low output lines
- Active-low and active-high enable inputs for flexible control
Applications
The SN74AHC138DG4 is suitable for various high-performance digital systems, including:
- High-speed memory decoding and data-routing applications
- Demultiplexing applications where an enable input can be used as a data input
- Cascading decoders to implement larger decoding systems (e.g., 24-line or 32-line decoders)
- Systems requiring short propagation-delay times to minimize system decoding delays
Q & A
- What is the operating voltage range of the SN74AHC138DG4?
The operating voltage range is from 2V to 5.5V.
- What types of applications is the SN74AHC138DG4 designed for?
It is designed for high-performance memory-decoding and data-routing applications.
- How many enable inputs does the SN74AHC138DG4 have?
The device has three enable inputs: two active-low and one active-high.
- What is the propagation delay time of the SN74AHC138DG4?
The propagation delay time is approximately 5.7 to 9.5 ns for a load capacitance of 15pF.
- What is the package type of the SN74AHC138DG4?
The package type is 16-SOIC (0.154", 3.90mm Width).
- Does the SN74AHC138DG4 have ESD protection?
Yes, it exceeds JESD 22 standards with 2000V Human-Body Model and 1000V Charged-Device Model protection.
- Can the SN74AHC138DG4 be used in demultiplexing applications?
Yes, an enable input can be used as a data input for demultiplexing applications.
- How many output lines does the SN74AHC138DG4 have?
The device has eight output lines, with one output line active-low at a time based on the input selection.
- What is the continuous output current rating of the SN74AHC138DG4?
The continuous output current rating is ±25 mA.
- Is the SN74AHC138DG4 suitable for cascading to implement larger decoding systems?
Yes, it is suitable for cascading to implement larger decoding systems such as 24-line or 32-line decoders.
