Description

The 7485 4-Bit Magnitude Comparator is a high-speed TTL logic IC designed for comparing two 4-bit binary numbers. This versatile IC belongs to the 7400 series of TTL logic devices and is widely used in digital systems, arithmetic logic units (ALUs), microprocessor interfaces, and educational projects. Packaged in a 16-pin Dual Inline Package (DIP), the 7485 provides a simple and reliable method to determine whether one 4-bit binary input is less than, equal to, or greater than another.

The 7485 magnitude comparator is essential when digital systems need to make decisions based on the relative size of binary numbers. For example, it can be used in digital sorting circuits, priority encoders, memory address comparison, and arithmetic operations. The IC can also be cascaded to compare numbers larger than 4 bits by connecting multiple comparators in series.

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⚙️ Key Features:

• Function: 4-bit magnitude comparator

• Logic Family: TTL (Transistor-Transistor Logic)

• Inputs: Two 4-bit binary numbers (A and B)

• Outputs: A>B, A=B, A<B

• Cascadable: Allows extension to 8-bit, 12-bit, or higher comparisons

• High-Speed Operation: Fast response suitable for real-time digital circuits

• Low Power Dissipation: Efficient operation in TTL systems

• Standard 16-Pin DIP Package: Easy integration with breadboards and PCBs

• Operating Voltage: 4.75V to 5.25V typical (5V logic systems)

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🧩 Pin Configuration (16-Pin DIP):

This pinout allows the 7485 to compare two 4-bit numbers simultaneously and output the result in a straightforward logic format.

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⚡ Electrical Characteristics:

• Supply Voltage: 5V TTL standard

• Input High Voltage (VIH): ≥ 2.0V

• Input Low Voltage (VIL): ≤ 0.8V

• Output Current: ±8 mA typical

• Propagation Delay: 18–22 ns (typical)

• Power Dissipation: 50–100 mW

These specifications ensure fast and accurate comparison for real-time applications.

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🧠 How It Works:

The 7485 IC compares binary numbers A and B on a bit-by-bit basis, starting from the most significant bit (MSB) to the least significant bit (LSB). Based on the comparison:

• A>B output is HIGH if A is larger than B

• A=B output is HIGH if A equals B

• A<B output is HIGH if A is smaller than B

This makes the IC extremely useful for conditional operations in arithmetic and logic circuits.

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🛠️ Applications:

• Digital Sorting and Ranking Systems – Determine the largest or smallest number

• Arithmetic Logic Units (ALUs) – Compare operands in calculations

• Microprocessor Address Comparators – Verify addresses in memory selection

• Priority Encoders – Select higher-priority signals

• Digital Counters – Compare counter value to a preset threshold

• Educational Training Kits – Learn binary number comparison and logic

• Embedded Systems – Implement decision-making logic in microcontrollers or FPGAs

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💡 Advantages:

• Allows direct 4-bit binary comparison with three clear outputs

• Cascadable design for larger number comparison

• High-speed and TTL-compatible for digital logic circuits

• Low power dissipation and stable operation

• Easy to use in breadboards, PCBs, and educational projects

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📦 Package Includes:

• 1 × 7485 4-Bit Magnitude Comparator IC (DIP-16)

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📘 Conclusion:

The 7485 DIP 4-Bit Magnitude Comparator is a versatile, reliable, and high-speed TTL IC that simplifies the task of comparing two binary numbers in digital systems. Its cascadable design, fast operation, and three output indicators (A>B, A=B, A<B) make it essential for designing counters, ALUs, memory comparators, and digital decision circuits. Whether for learning or professional applications, the 7485 provides accuracy, efficiency, and ease of integration for all types of digital projects.