74139
74139 Dual 2-to-4 Line Decoder/Demultiplexer
Overview
The 74139 is a high-speed, dual 2-to-4 line decoder/demultiplexer integrated circuit designed for digital logic applications. This TTL-compatible device features two independent decoders, each accepting two binary-weighted inputs (A0 and A1) and providing four mutually exclusive active-low outputs (Y0 to Y3). The 74139 is commonly used in memory address decoding, data routing, and other digital systems where binary-to-line decoding is required.
Each decoder section includes an active-low enable input (E) that when high forces all outputs of that decoder to their inactive (high) state. When the enable input is low, the selected output (determined by the binary input) goes low while all other outputs remain high. This functionality makes the device suitable for both decoding and demultiplexing applications.
Features
- High-speed operation with typical propagation delay of 21ns
- Dual 2-line to 4-line decoders in single package
- Active-low outputs for direct interface with common logic families
- Active-low enable input for output control
- TTL-compatible inputs and outputs
- Wide operating voltage range: 4.75V to 5.25V
- Low power consumption: typically 32mW
- Designed for bus-oriented systems
- High noise immunity: 0.45V (min) noise margin
- Standard 16-pin DIP and SOIC package options
Applications
- Memory address decoding in microprocessor systems
- Data routing and demultiplexing
- Input/output port selection
- Function generation in digital systems
- Code conversion circuits
- Peripheral selection in embedded systems
- Test equipment and instrumentation
- Digital display drivers
- General purpose logic implementations
Electrical Characteristics
Absolute Maximum Ratings
| Parameter | Value | Unit |
|---|---|---|
| Supply Voltage (Vcc) | 7 | V |
| Input Voltage | 5.5 | V |
| Operating Free Air Temperature | 0 to +70 | °C |
| Storage Temperature Range | -65 to +150 | °C |
Recommended Operating Conditions
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (Vcc) | 4.75 | 5.0 | 5.25 | V |
| High-Level Input Voltage | 2.0 | - | - | V |
| Low-Level Input Voltage | - | - | 0.8 | V |
| Operating Ambient Temperature | 0 | - | 70 | °C |
Switching Characteristics (Vcc = 5V, TA = 25°C)
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Propagation Delay (Input to Output) | - | 15 | 21 | ns |
| Output Transition Time | - | 10 | 15 | ns |
| Enable Time (E to Y) | - | 18 | 27 | ns |
| Disable Time (E to Y) | - | 15 | 22 | ns |
Package Information
16-Pin DIP (Dual Inline Package)
- Package Code: N
- Package Type: Plastic DIP
- Lead Count: 16
- Body Width: 0.3 inch (7.62mm)
- Body Length: 0.8 inch (20.32mm)
- Lead Pitch: 0.1 inch (2.54mm)
- Operating Temperature Range: 0°C to +70°C
- Moisture Sensitivity Level (MSL): 1 (Unlimited)
16-Pin SOIC (Small Outline Integrated Circuit)
- Package Code: D
- Package Type: Plastic SOIC
- Lead Count: 16
- Body Width: 0.154 inch (3.9mm)
- Body Length: 0.386 inch (9.8mm)
- Lead Pitch: 0.05 inch (1.27mm)
- Operating Temperature Range: 0°C to +70°C
- Moisture Sensitivity Level (MSL): 1 (Unlimited)
