Overview
The SN74ALS138ADR is a 3-line to 8-line decoder/demultiplexer produced by Texas Instruments. This device is designed for high-performance memory-decoding or data-routing applications, particularly in systems that require very short propagation delay times. It is part of the ALS and AS series, known for their high-speed capabilities and suitability for use in high-performance systems.
The device incorporates three enable inputs (G1, G2A, and G2B) which simplify cascading and data reception. It is available in various package options, including Plastic Small-Outline (D) packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs.
Key Specifications
| Parameter | Unit | Min | Nom | Max |
|---|---|---|---|---|
| Supply Voltage (VCC) | V | 4.5 | 5 | 5.5 |
| High-Level Input Voltage (VIH) | V | 2 | 2 | 2 |
| Low-Level Input Voltage (VIL) | V | 0.7 | 0.8 | 0.8 |
| High-Level Output Current (IOH) | mA | -0.4 | -0.4 | -0.4 |
| Low-Level Output Current (IOL) | mA | 4 | 8 | 8 |
| Operating Free-Air Temperature (TA) | °C | 0 | - | 70 |
| Propagation Delay Time (tPLH) from A, B, C to Any Y | ns | 5 | - | 22 |
| Propagation Delay Time (tPHL) from A, B, C to Any Y | ns | 6 | - | 18 |
Key Features
- Designed for high-performance memory-decoding or data-routing applications.
- Three enable inputs (G1, G2A, and G2B) to simplify cascading and data reception.
- Very short propagation delay times, making it suitable for high-speed systems.
- Can be used to minimize the effects of system decoding when employed with high-speed memories.
- Available in various package options: Plastic Small-Outline (D), Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs.
- Operates over a temperature range of 0°C to 70°C for the SN74ALS138A series.
Applications
- High-performance memory-decoding systems.
- Data-routing applications requiring fast propagation delay times.
- Cascaded decoder systems where multiple decoders are used to expand the number of output lines.
- Demultiplexing applications where an enable input can be used as a data input.
- High-speed data transmission systems.
Q & A
- What is the primary function of the SN74ALS138ADR?
The SN74ALS138ADR is a 3-line to 8-line decoder/demultiplexer designed for high-performance memory-decoding or data-routing applications.
- What are the key package options available for the SN74ALS138ADR?
The device is available in Plastic Small-Outline (D) packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs.
- What is the operating temperature range for the SN74ALS138ADR?
The operating temperature range is from 0°C to 70°C.
- How many enable inputs does the SN74ALS138ADR have?
The device has three enable inputs: G1, G2A, and G2B.
- What is the typical propagation delay time for the SN74ALS138ADR?
The propagation delay time from A, B, C to any Y is typically between 5 ns and 22 ns.
- Can the SN74ALS138ADR be used in demultiplexing applications?
- What is the maximum supply voltage for the SN74ALS138ADR?
The maximum supply voltage is 5.5 V.
- How many output lines does the SN74ALS138ADR have?
The device has 8 output lines (Y0 to Y7).
- Is the SN74ALS138ADR suitable for high-speed memory systems?
- What are the typical high-level and low-level output currents for the SN74ALS138ADR?
The typical high-level output current is -0.4 mA, and the typical low-level output current is 8 mA.
