74HC390 Dual Decade Counter IC – High-Speed CMOS 4-Bit Ripple Counter for Frequency Division

Overview 

The 74HC390 is a dual 4-bit ripple-through decade counter. Each half of the IC is partitioned into a divide-by-two and a divide-by-five section. This “Dual” nature allows you to count from 0 to 99 on a single chip, or perform complex frequency division, such as dividing a clock signal by 2, 5, 10, 20, 25, 50, or even 100. As part of the 74HC series, it offers significantly lower power consumption and a wider voltage range than older TTL (LS) chips.

Key Features 

• Dual Independent Counters: Two separate 4-bit decade counters in one 16-pin DIP package.

• High-Speed CMOS: Faster than standard 4000 series and more power-efficient than 74LS series.

• Versatile Division: Capable of multiple frequency division ratios (1/2, 1/5, 1/10, 1/20, 1/50, 1/100).

• Wide Voltage Range: Operates reliably from 22Vo 6V DC, making it perfect for both 3.3V (ESP32) and 5V (Arduino) logic.

• Space Saving: Replaces two 74LS90 ICs, reducing the size and complexity of your circuit boards.

Technical Specifications 

Ideal Applications

• Digital Clocks: One chip can handle both the “Seconds” and “Minutes” units.

• Frequency Synthesizers: Dividing high-frequency oscillators down to usable timing pulses.

• Event Counters: Building compact 2-digit decimal counters for industrial sensing.

• Educational Training: Teaching the difference between CMOS and TTL logic in advanced DLD labs.