74145 BCD to Decimal Decoder/Driver IC (DIP)

Overview: 74145 BCD to Decimal Decoder/Driver IC (DIP)

The 74145 BCD to Decimal Decoder/Driver IC (DIP) converts a 4-bit Binary-Coded Decimal (BCD) input into one active LOW output among ten outputs, providing a one-of-ten decoding function. Packaged in a standard 24-pin Dual In-line Package (DIP), the 74145 is widely used for display selection, device enabling, and simple control tasks in TTL-based digital systems.

Key Features

• 4-bit BCD input to 1-of-10 decimal output decoding
• Active LOW outputs for direct sinking drive capability
• Standard 24-pin DIP footprint suitable for breadboards and PCBs
• Compatible with TTL logic families
• Outputs can sink current to drive LEDs, lamps, or relay coils with appropriate external components
• Reliable and commonly used in educational and practical circuit designs

Technical Details and Electrical Characteristics

• Input: 4-bit BCD (0 to 9 valid codes)
• Output: Ten mutually exclusive active LOW outputs
• Package: 24-pin Dual In-line Package (DIP)
• Logic family compatibility: TTL
• Typical use: sinking outputs to drive LEDs or switching transistors for larger loads

Typical Applications

• Driving decimal displays and multiplexed display systems
• Keypad encoding and decoding for key-scan matrices
• LED and lamp selection and control
• Device selection in multiplexed or shared-bus systems
• Decimal counting systems and sequential circuit designs
• Educational projects and digital logic experimentation

Why Choose the 74145 for Your Project

The 74145 is a straightforward, reliable decoder that simplifies converting BCD data into a single selected output. Its active LOW outputs and ability to sink current make it convenient for driving LEDs directly or controlling external transistors for heavier loads. The DIP package allows quick prototyping on breadboards and easy replacement on PCBs, making it a staple component for students, hobbyists, and engineers.

Design Tips and Usage Notes

• Remember outputs are active LOW; connect loads between VCC and the outputs or use transistors when switching higher voltages or currents.
• Use current-limiting resistors when directly driving LEDs to prevent damage.
• Validate that BCD inputs remain within the TTL voltage thresholds for reliable operation.
• For multiplexed displays, consider using the 74145 in combination with counters and timing circuitry to sequence outputs.

Ordering and Handling

Available in standard 24-pin DIP packaging for easy prototyping. Handle ICs using anti-static precautions to avoid damage from electrostatic discharge.

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