Overview
The 74HC138D, produced by NXP USA Inc. (now part of Nexperia), is a 3-to-8 line decoder/demultiplexer with inverting outputs. This CMOS device decodes three binary weighted address inputs (A0, A1, and A2) to eight mutually exclusive outputs (Y0 to Y7). It features three enable inputs (E1, E2, and E3), allowing for easy parallel expansion and demultiplexing capabilities. The device is part of the 74HC/HCT family, known for its high speed and low power consumption, making it suitable for a wide range of applications from automotive and industrial to consumer electronics.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage | 2.0 | 5.0 | 6.0 | V |
| VI Input Voltage | 0 | - | VCC | V |
| VO Output Voltage | 0 | - | VCC | V |
| Tamb Ambient Temperature | -40 | - | 125 | °C |
| Input Transition Rise and Fall Rate | - | 1.67 | 139 | ns/V |
| Output Drive Capability | - | - | ±5.2 | mA |
| Power Dissipation | - | - | 500 | mW |
| Propagation Delay (A to Y) | - | 15 | 45 | ns |
Key Features
- Wide Supply Voltage Range: Operates from 2.0 V to 6.0 V.
- CMOS Low Power Dissipation: Low power consumption, making it energy-efficient.
- High Noise Immunity: Ensures reliable operation in noisy environments.
- Multiple Enable Inputs: Three enable inputs (E1, E2, and E3) for easy parallel expansion and demultiplexing.
- Active LOW Mutually Exclusive Outputs: Only one output is active LOW while the others are HIGH.
- ESD Protection: Compliant with ANSI/ESDA/JEDEC JS-001 Class 2 (exceeds 2000 V) and JS-002 Class C3 (exceeds 1000 V).
- Operating Temperature Range: Specified from -40 °C to +125 °C.
- Package Options: Available in SO16, TSSOP16, and DHVQFN16 packages.
Applications
- Memory Chip Select Decoding: Ideal for selecting memory chips based on address inputs.
- Demultiplexing: Can be used as an eight-output demultiplexer by using one of the active LOW enable inputs as the data input.
- Industrial and Automotive Systems: Suitable for use in industrial and automotive applications due to its robustness and wide operating temperature range.
- Consumer Electronics: Used in various consumer electronic devices requiring decoding and demultiplexing functions.
- Embedded Systems: Useful in embedded systems where multiple outputs need to be controlled based on a few input lines.
Q & A
- What is the primary function of the 74HC138D?
The primary function of the 74HC138D is to decode three binary weighted address inputs to eight mutually exclusive outputs.
- What is the supply voltage range for the 74HC138D?
The supply voltage range is from 2.0 V to 6.0 V.
- How many enable inputs does the 74HC138D have?
The device has three enable inputs: E1, E2, and E3.
- What is the operating temperature range of the 74HC138D?
The operating temperature range is from -40 °C to +125 °C.
- Is the 74HC138D RoHS compliant?
Yes, the 74HC138D is RoHS compliant.
- What are the package options available for the 74HC138D?
The device is available in SO16, TSSOP16, and DHVQFN16 packages.
- How does the 74HC138D handle ESD protection?
The device has ESD protection compliant with ANSI/ESDA/JEDEC JS-001 Class 2 (exceeds 2000 V) and JS-002 Class C3 (exceeds 1000 V).
- Can the 74HC138D be used as a demultiplexer?
Yes, it can be used as an eight-output demultiplexer by using one of the active LOW enable inputs as the data input.
- What is the propagation delay of the 74HC138D?
The propagation delay from address inputs to outputs is typically around 15 ns to 45 ns depending on the supply voltage.
- Is the 74HC138D suitable for industrial applications?
Yes, it is suitable for industrial applications due to its robustness and wide operating temperature range.
