SN74HC138DR

Product Overview

• Category: Integrated Circuit
• Use: Decoder/Demultiplexer
• Characteristics:
  • High-Speed CMOS Logic
  • Low Power Consumption
  • Wide Operating Voltage Range
  • Schmitt-Trigger Inputs
• Package: SOIC (Small Outline Integrated Circuit)
• Essence: Decodes a 3-bit binary input to one of eight outputs
• Packaging/Quantity: Tape and Reel, 2500 units per reel

Specifications

• Supply Voltage Range: 2V to 6V
• Input Voltage Range: 0V to VCC
• Output Voltage Range: 0V to VCC
• Maximum Input Current: ±1µA
• Maximum Output Current: ±25mA
• Propagation Delay Time: 13ns (typical)
• Operating Temperature Range: -40°C to +85°C

Detailed Pin Configuration

The SN74HC138DR has a total of 16 pins. The pin configuration is as follows:

1. GND (Ground)
2. A0 (Address Input 0)
3. A1 (Address Input 1)
4. A2 (Address Input 2)
5. /G1 (Enable Input)
6. Y0 (Output 0)
7. Y1 (Output 1)
8. Y2 (Output 2)
9. Y3 (Output 3)
10. Y4 (Output 4)
11. Y5 (Output 5)
12. Y6 (Output 6)
13. Y7 (Output 7)
14. VCC (Supply Voltage)
15. /G2A (Enable Input)
16. /G2B (Enable Input)

Functional Features

The SN74HC138DR is a 3-to-8 line decoder/demultiplexer. It takes a 3-bit binary input and selects one of the eight outputs based on the input combination. The decoder has three enable inputs (/G1, /G2A, /G2B) that control the operation of the device.

Advantages and Disadvantages

Advantages: - High-speed operation - Low power consumption - Wide operating voltage range - Schmitt-trigger inputs for noise immunity

Disadvantages: - Limited to 3-bit decoding - Not suitable for applications requiring higher bit decoding

Working Principles

The SN74HC138DR uses CMOS logic to decode the 3-bit binary input. The enable inputs (/G1, /G2A, /G2B) determine whether the decoder is active or not. When enabled, the decoder selects one of the eight outputs based on the input combination. The selected output is driven low while all other outputs remain high.

Detailed Application Field Plans

The SN74HC138DR is commonly used in various digital systems where decoding and demultiplexing functions are required. Some application fields include:

1. Address Decoding: Used in microcontrollers and memory systems to select specific addresses.
2. Data Demultiplexing: Used to route data from a single source to multiple destinations.
3. LED Matrix Control: Used to control individual LEDs in a matrix display.
4. Multiplexer Control: Used to select one of multiple inputs for further processing.

Detailed and Complete Alternative Models

Some alternative models to SN74HC138DR that provide similar functionality are:

1. CD74HC138E by Texas Instruments
2. 74HC138N by NXP Semiconductors
3. DM74LS138N by Fairchild Semiconductor
4. MC74HC138AN by ON Semiconductor

These alternative models offer comparable features and can be used as substitutes depending on specific requirements.

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