74147 10-to-4 Line Priority Encoder IC (DIP)

Overview

The 74147 10-to-4 Line Priority Encoder IC (DIP) is a TTL logic device that converts up to ten active-low input lines into a 4-bit binary output. With built-in priority encoding, when multiple inputs are active at the same time the device will present the binary code for the highest-priority input. Packaged in a standard 16-pin Dual In-Line Package (DIP), it is ideal for breadboard prototyping and PCB integration.

Key Features

• 10-to-4 line priority encoding
• Active-low inputs and active-low outputs
• Outputs the binary code of the highest-priority active input
• Standard 16-pin DIP package for easy handling and prototyping
• Compatible with 74-series TTL logic families
• Widely used in keypad encoders, input compression, and digital control circuits

How It Works

The encoder monitors ten active-low inputs. If one input is asserted (logic low), the device outputs a 4-bit binary code representing that input. If multiple inputs are asserted simultaneously, the priority logic ensures the lowest-numbered input (the highest priority) is encoded and presented on the outputs. Because inputs and outputs are active-low, external pull-up resistors or appropriate driving logic are commonly used to define idle states.

Technical Details

• Inputs: 10 active-low inputs
• Outputs: 4-bit binary active-low outputs
• Encoding type: Priority encoder (highest-priority input wins)
• Package: 16-pin Dual In-Line Package (DIP)
• Logic family: 74-series TTL compatibility

Applications

• Keypad and keyboard encoding
• Digital input compression to reduce I/O usage
• Data acquisition front-ends where multiple signals must be prioritized
• Control systems requiring deterministic priority handling
• Signal multiplexing and interface logic in embedded systems

Integration Tips

• Because inputs are active-low, use pull-up resistors or open-collector drivers when interfacing mechanical switches or open-drain outputs.
• Ensure proper TTL-level compatibility when connecting to other logic devices to avoid level mismatch issues.
• Use standard DIP sockets during prototyping to simplify IC replacement and reduce heat stress on the component.

Package and Handling

The 74147 is supplied in a standard 16-pin DIP package that fits common breadboards and PCB footprints. Its form factor makes it suitable for rapid prototyping as well as final board designs that use through-hole components.

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