Overview
The SN74AHC138DR is a 3-Line to 8-Line Decoder/Demultiplexer 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 particularly useful in high-speed memory systems where it can minimize the effects of system decoding, ensuring that the delay times of the decoders and the enable time of the memory are typically less than the access time of the memory.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage | 2 | 5.5 | V | |
| VIH High-Level Input Voltage (VCC = 5.5V) | 3.85 | 3.85 | V | |
| VIL Low-Level Input Voltage (VCC = 5.5V) | 1.65 | 1.65 | V | |
| IOH High-Level Output Current (VCC = 5V) | -8 | -8 | mA | |
| IOL Low-Level Output Current (VCC = 5V) | 8 | 8 | mA | |
| TA Operating Free-Air Temperature | -40 | 85 | °C | |
| tPLH Propagation Delay Time (VCC = 5V, CL = 15pF) | 5.7 | 8.1 | 9.5 | ns |
| tPHL Propagation Delay Time (VCC = 5V, CL = 15pF) | 5.7 | 8.1 | 9.5 | ns |
Key Features
- Operating range: 2V to 5.5V VCC
- Designed specifically for high-speed memory decoders and data-transmission systems
- Incorporate 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 and 1000V Charged-Device Model
- Available in various packages including SOIC, SSOP, TVSOP, PDIP, SOP, TSSOP, and VQFN
Applications
The SN74AHC138DR is used in high-performance memory-decoding and data-routing applications. It is particularly useful in:
- High-speed memory systems to minimize system decoding delays
- Data transmission systems requiring fast enable circuits
- Cascading and data reception applications due to its three enable inputs
- 24-bit and 32-bit decoding schemes as illustrated in the application information section of the datasheet
Q & A
- What is the operating voltage range of the SN74AHC138DR?
The operating voltage range is from 2V to 5.5V VCC.
- What are the key applications of the SN74AHC138DR?
It is used in high-speed memory systems and data transmission systems, particularly for decoding and demultiplexing.
- What is the propagation delay time of the SN74AHC138DR?
The propagation delay time is typically around 8.1 ns for VCC = 5V and CL = 15pF.
- What ESD protection does the SN74AHC138DR offer?
It offers ESD protection exceeding JESD 22: 2000V Human-Body Model and 1000V Charged-Device Model.
- What are the available package options for the SN74AHC138DR?
It is available in SOIC, SSOP, TVSOP, PDIP, SOP, TSSOP, and VQFN packages.
- What is the maximum continuous output current of the SN74AHC138DR?
The maximum continuous output current is ±25 mA.
- What is the operating temperature range of the SN74AHC138DR?
The operating temperature range is from -40°C to 85°C.
- How many enable inputs does the SN74AHC138DR have?
It has three enable inputs to simplify cascading and/or data reception.
- What is the latch-up performance of the SN74AHC138DR?
The latch-up performance exceeds 250mA per JESD 17.
- What is the typical power dissipation capacitance of the SN74AHC138DR?
The typical power dissipation capacitance is 13 pF at no load and f = 1 MHz.
