Overview
The MC74HCT138ADR2G is a 1-of-8 decoder/demultiplexer produced by onsemi. This device is part of the MC74HCT series, which is designed to interface directly with TTL (Transistor-Transistor Logic) and NMOS (N-type Metal-Oxide-Semiconductor) outputs to high-speed CMOS (Complementary Metal-Oxide-Semiconductor) inputs. It decodes a three-bit address to one of eight active-low outputs, making it versatile for various digital circuit applications.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| DC Supply Voltage (VCC) | 4.5 to 5.5 | V |
| DC Input Voltage (VIN) | 0 to VCC + 0.5 | V |
| DC Output Voltage (VOUT) | 0 to VCC + 0.5 | V |
| Operating Free-Air Temperature (TA) | -55 to +125 | °C |
| Input Rise or Fall Time | 500 | ns |
| Maximum Propagation Delay, Input A to Output Y | 30 to 45 | ns |
| Maximum Propagation Delay, CS1 to Output Y | 27 to 41 | ns |
| Maximum Output Transition Time | 15 to 22 | ns |
| Maximum Input Capacitance | 10 | pF |
| Power Dissipation Capacitance (Per Package) | 51 | pF |
| Maximum Quiescent Supply Current (ICC) | 4 to 160 | µA |
Key Features
- Output Drive Capability: 10 LSTTL Loads
- Outputs directly interface to CMOS, NMOS, and TTL
- Low Input Current: 1.0 µA
- High Noise Immunity characteristic of CMOS devices
- In compliance with the requirements defined by JEDEC Standard No. 7A
- Chip Complexity: 122 FETs or 30.5 equivalent gates
- Three Chip Select inputs (two active-low and one active-high) for demultiplexing, cascading, and chip-selecting functions
Applications
The MC74HCT138ADR2G is suitable for a variety of digital circuit applications, including:
- Demultiplexing and decoding in digital systems
- Cascading multiple decoders for larger address spaces
- Level conversion between TTL/NMOS and CMOS logic levels
- Control and selection circuits in microprocessor and microcontroller systems
- General-purpose digital logic circuits requiring decoding and demultiplexing functions
Q & A
- What is the primary function of the MC74HCT138ADR2G?
The primary function is to decode a three-bit address to one of eight active-low outputs, acting as a 1-of-8 decoder/demultiplexer.
- What is the operating voltage range for the MC74HCT138ADR2G?
The operating voltage range is 4.5 to 5.5 volts.
- How many chip select inputs does the MC74HCT138ADR2G have?
The device has three chip select inputs: two active-low and one active-high.
- What is the maximum propagation delay from input A to output Y?
The maximum propagation delay from input A to output Y is between 30 to 45 nanoseconds.
- Is the MC74HCT138ADR2G compatible with TTL and NMOS outputs?
Yes, it is designed to interface directly with TTL and NMOS outputs to high-speed CMOS inputs.
- What is the maximum quiescent supply current for the MC74HCT138ADR2G?
The maximum quiescent supply current is between 4 to 160 microamperes.
- What are the typical applications of the MC74HCT138ADR2G?
Typical applications include demultiplexing and decoding in digital systems, cascading multiple decoders, level conversion, and control and selection circuits in microprocessor and microcontroller systems.
- What is the maximum input capacitance of the MC74HCT138ADR2G?
The maximum input capacitance is 10 picofarads.
- How many outputs does the MC74HCT138ADR2G have?
The device has eight active-low decoded outputs (Y0 to Y7).
- What is the thermal resistance of the SOIC-16 package for the MC74HCT138ADR2G?
The thermal resistance for the SOIC-16 package is approximately 126 °C/W.
