Overview
The MC74HC138AD, produced by onsemi, is a high-performance CMOS 3-to-8 line decoder/demultiplexer. This device is designed to decode a three-bit binary weighted address to one of eight active-low outputs. It is compatible with standard CMOS outputs and, with pull-up resistors, can also interface with LSTTL outputs. The MC74HC138AD features three chip select inputs, two active-low and one active-high, which facilitate demultiplexing, cascading, and chip-selecting functions.
Key Specifications
| Parameter | Min | Max | Unit |
|---|---|---|---|
| VCC (Supply Voltage) | 2.0 | 6.0 | V |
| VIN, VOUT (DC Input, Output Voltage) | 0 | VCC | V |
| TA (Operating Free-Air Temperature) | -55 | 125 | °C |
| VIH (Minimum High-Level Input Voltage) | 1.5 | 4.2 | V |
| VIL (Maximum Low-Level Input Voltage) | 0.5 | 1.8 | V |
| IIN (Maximum Input Leakage Current) | ±1.0 | µA | |
| ICC (Maximum Quiescent Supply Current) | 4 | 160 | µA |
| tPLH, tPHL (Maximum Propagation Delay) | 23 | 205 | ns |
| tr, tf (Maximum Input Rise and Fall Time) | 400 | 1000 | ns |
Key Features
- Wide supply voltage range from 2.0V to 6.0V.
- CMOS low power consumption and high noise immunity.
- Sinks or sources 8 mA at VCC = 4.5V.
- Schmitt Trigger Action at all inputs.
- ESD protection tested per JESD 22 standards (exceeds 200-V Machine Model, 2000-V Human Body Model, and 1000-V Charged Device Model).
- Totally lead-free and fully RoHS compliant.
- Open-drain outputs for flexible interface options.
- High-speed CMOS design for efficient performance.
- Compact surface mount package (16-TSSOP) suitable for automated assembly and high-density PCB designs).
Applications
- Memory chip select decoding).
- Demultiplexing).
- Single line peripheral control).
- Data routing and selection in digital systems).
- Peripheral device control and selection).
- General-purpose logic switching and multiplexing).
Q & A
- What is the primary function of the MC74HC138AD?
The MC74HC138AD is a 3-to-8 line decoder/demultiplexer that decodes a three-bit binary weighted address to one of eight active-low outputs.
- What is the operating voltage range of the MC74HC138AD?
The operating voltage range is from 2.0V to 6.0V.
- What types of inputs does the MC74HC138AD have?
The device has three chip select inputs: two active-low (E1 and E2) and one active-high (E3).
- What is the significance of Schmitt Trigger Action in the MC74HC138AD?
Schmitt Trigger Action at all inputs helps in improving noise immunity.
- Is the MC74HC138AD RoHS compliant?
Yes, the MC74HC138AD is totally lead-free and fully RoHS compliant.
- What are the typical applications of the MC74HC138AD?
Typical applications include memory chip select decoding, demultiplexing, single line peripheral control, data routing, and peripheral device control.
- What is the maximum propagation delay of the MC74HC138AD?
The maximum propagation delay ranges from 23 ns to 205 ns depending on the supply voltage.
- What is the maximum input leakage current of the MC74HC138AD?
The maximum input leakage current is ±1.0 µA.
- Is the MC74HC138AD suitable for high-density PCB designs?
Yes, it is available in a compact 16-TSSOP package suitable for automated assembly and high-density PCB designs.
- What is the maximum quiescent supply current of the MC74HC138AD?
The maximum quiescent supply current is 160 µA.
