7490 74ls90 Ic Decade Counter

The 7490 / 74LS90 Decade Counter IC is a 4-bit synchronous counter consisting of a divide-by-2 section and a divide-by-5 section, which can be cascaded to form divide-by-10 counters. It is one of the most commonly used counters in digital electronics, clock circuits, and frequency division applications.

The IC can be configured for decade counting (0–9) or binary division, making it versatile in timer circuits, digital displays, and sequencing applications. It is available in a DIP-14 package, compatible with breadboards and PCBs.

🔹 Applications

• Digital clocks and time counters

• Frequency divider circuits

• Event counters and scoreboards

• Timers and sequencing applications

• Digital display drivers (with 7-segment decoders like 7447)

• Traffic light controller projects

• Educational and DIY electronics

🔹 Precautions

• Ensure correct wiring of reset pins (R0, R9) for proper operation

• Do not exceed maximum supply voltage (7V for 74 series, 5.5V for LS series)

• Provide debounced input signals for accurate counting

• Use proper decoupling capacitors to reduce noise

• Handle carefully to avoid static discharge damage (ESD)

🔹 Technical Specifications

• IC Type: 4-bit Binary Decade Counter

• Series: 7490 / 74LS90

• Package: DIP-14

• Counter Type: Divide-by-2 and Divide-by-5 sections

• Supply Voltage (Vcc): 4.75V – 5.25V (74LS90), up to 7V max (7490)

• Logic Type: TTL (Transistor-Transistor Logic)

• Maximum Clock Frequency: ~42 MHz (74LS90)

• Operating Temperature: 0°C to +70°C

• Outputs: Q0, Q1, Q2, Q3 (binary counter outputs)

📹 Tutorial Video

Watch 7490 Decade Counter Tutorial

🔹 Related Categories

• IC’s

• Electronics Components

• Arduino and Accessories

• Tools and Accessories

🔹 Summary

The 7490 / 74LS90 Decade Counter IC is a versatile 4-bit counter used in frequency dividers, digital clocks, timers, and sequencing circuits. With divide-by-2 and divide-by-5 sections, it is widely adopted in both DIY projects and professional digital systems. A must-have in IC’s for digital electronics enthusiasts.