onsemi MC74AC4040DR2G 12-Stage Binary Ripple Counter: Datasheet, Pinout, and Application Circuits

The onsemi MC74AC4040DR2G is a high-performance, 12-stage binary ripple counter fabricated with advanced CMOS technology. This integrated circuit is designed for a wide range of digital applications requiring frequency division, timing, and control. Its operation is characterized by a ripple effect, where each flip-flop triggers the next, making it an efficient solution for counting and dividing clock signals.

Key Features from the Datasheet

The device operates over a broad voltage range, typically from 2.0V to 6.0V, making it compatible with both 3.3V and 5V systems. It offers high noise immunity and can source/sink up to 24mA of output current, allowing it to drive LEDs or other peripherals directly. A key feature is its asynchronous master reset (MR) pin. When a high logic level is applied to this pin, all counter outputs (Q0 through Q11) are reset to a low state immediately, independent of the clock signal. The maximum clock frequency can exceed 100 MHz at 5V, enabling its use in high-speed counting applications.

Pinout Configuration

Housed in a common SOIC-16 package, the pinout is crucial for circuit design:

Pin 1 (Q12): Output of the 12th stage (÷4096).

Pin 2 (Q13): Output of the 13th stage (Note: This is a 12-stage counter; Q13 is not connected internally).

Pin 3 (Q14): Output of the 14th stage (Not connected).

Pin 4 (Q6): Output of the 6th stage (÷64).

Pin 5 (Q5): Output of the 5th stage (÷32).

Pin 6 (Q7): Output of the 7th stage (÷128).

Pin 7 (Q4): Output of the 4th stage (÷16).

Pin 8 (VSS): Ground (0V).

Pin 9 (Q3): Output of the 3rd stage (÷8).

Pin 10 (Q2): Output of the 2nd stage (÷4).

Pin 11 (Q1): Output of the 1st stage (÷2).

Pin 12 (Q0): Output of the 0th stage (Clock Input).

Pin 13 (Q9): Output of the 9th stage (÷512).

Pin 14 (Q8): Output of the 8th stage (÷256).

Pin 15 (Q10): Output of the 10th stage (÷1024).

Pin 16 (Q11): Output of the 11th stage (÷2048).

Pin 17 (MR): Master Reset (Active HIGH).

Pin 18 (CP): Clock Input (Negative-edge triggered).

Application Circuits

1. Frequency Divider: The primary use of the MC74AC4040 is as a programmable frequency divider. By tapping different output pins (Qn), you can obtain a output frequency equal to the input clock frequency divided by 2^(n+1). For example, using Q11 provides a division ratio of 4096. This is invaluable in clock generation circuits for deriving lower frequencies from a single crystal oscillator.

2. Digital Timer: By combining the counter with an oscillator and the master reset function, it can create precise time delays. The time period is determined by the division ratio of the selected output and the period of the input clock (T = 1/f).

3. Event Counter: While ripple counters are not ideal for synchronous high-speed counting due to propagation delay, the MC74AC4040 is perfectly suitable for lower-speed event counting or in applications where the exact ripple timing is not critical.

ICGOODFIND Summary

The onsemi MC74AC4040DR2G is a versatile and robust 12-stage ripple counter that excels in frequency division and timing applications. Its high-speed operation, wide voltage range, and simple interface make it a reliable choice for digital designers. The inclusion of a master reset provides immediate control over the counting operation, enhancing its utility in state machine and control system design. For tasks requiring binary division from ÷2 to ÷4096, this IC remains a fundamental and highly effective component.

Keywords: Binary Ripple Counter, Frequency Divider, Master Reset, CMOS Technology, onsemi