Overview
The SN74ALS138A, produced by Texas Instruments, is a 3-line to 8-line decoder/demultiplexer designed for high-performance memory-decoding and data-routing applications. This Schottky-clamped TTL MSI circuit is optimized for use in systems requiring very short propagation delay times. It is particularly useful in high-speed memory systems where it can minimize the effects of system decoding, ensuring that the delay times introduced by the decoder are negligible compared to the memory's access time.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage | 4.5 | 5 | 5.5 | V |
| VIH High-Level Input Voltage | 2 | - | - | V |
| VIL Low-Level Input Voltage | 0.8 | - | - | V |
| IOH High-Level Output Current | -0.4 | - | - | mA |
| IOL Low-Level Output Current | 4 | - | 8 | mA |
| TA Operating Free-Air Temperature | 0 | - | 70 | °C |
| Package | SOIC (D), DIP, etc. | - | - | - |
| Pins | 16 | - | - | - |
Key Features
- Designed specifically for high-speed memory decoders and data transmission systems.
- Three enable inputs to simplify cascading and/or data reception.
- Schottky-clamped for high performance to suppress line-ringing and simplify system design.
- Fully buffered inputs, each representing only one normalized load to its driving circuit.
- Two active-low and one active-high enable inputs reduce the need for external gates or inverters when expanding.
Applications
- High-performance memory decoding in computer systems.
- Data-routing applications requiring very short propagation delay times.
- Demultiplexing applications where an enable input can be used as a data input.
- Cascading to implement larger decoders (e.g., 24-line or 32-line decoders) without external inverters).
Q & A
- What is the primary function of the SN74ALS138A?
The SN74ALS138A is a 3-line to 8-line decoder/demultiplexer designed for high-performance memory-decoding and data-routing applications).
- What are the key features of the SN74ALS138A?
Key features include three enable inputs, Schottky-clamped for high performance, and fully buffered inputs).
- What is the operating temperature range for the SN74ALS138A?
The operating temperature range is from 0°C to 70°C).
- What types of packages are available for the SN74ALS138A?
Available packages include SOIC (D), DIP, and others).
- How many pins does the SN74ALS138A have?
The SN74ALS138A has 16 pins).
- Can the SN74ALS138A be used in demultiplexing applications?
- How does the SN74ALS138A simplify system design?
- Can the SN74ALS138A be cascaded to implement larger decoders?
- What is the significance of the Schottky-clamped design in the SN74ALS138A?
- What are the typical applications of the SN74ALS138A?
