onsemi MC74HC08ADG Quad 2-Input AND Gate: Datasheet, Pinout, and Application Circuit Guide
The MC74HC08ADG from onsemi is a member of the high-speed CMOS (HC) logic family, integrating four independent 2-input AND gates into a single compact package. This IC is designed for a broad range of digital logic applications where high noise immunity and low power consumption are critical. Its robust performance and reliability make it a fundamental component in modern electronic design.
Datasheet Overview and Key Specifications
A thorough review of the datasheet is essential for proper circuit design. The MC74HC08ADG operates over a wide supply voltage range from 2.0V to 6.0V, allowing for compatibility with various logic levels, including 3.3V and 5V systems. Key electrical characteristics include:
High-Level Output Current: -4mA (min)
Low-Level Output Current: 4mA (min)
Propagation Delay: Typically 10 ns at 5V
Low Power Consumption: 2 µA (max) static current per gate
The device is housed in a SOIC-14 package, which is suitable for automated assembly processes. It is characterized for operation from -40°C to +85°C, ensuring functionality in industrial environments. The HC family offers significantly lower power consumption than the older 7408 TTL series while maintaining a similar pinout.
Pinout Configuration
Understanding the pinout is the first step to implementing the IC. The MC74HC08ADG in a 14-pin SOIC package has the following configuration:
Pins 1, 2, 5, 6, 8, 9, 12, 13: These are the input pins for the four AND gates.
Pins 3, 4, 10, 11: These are the output pins for the four AND gates.
Pin 7 (GND): This is the ground (0V) connection.
Pin 14 (VCC): This is the positive supply voltage pin.
Each gate functions according to the standard AND logic truth table: the output (Y) is HIGH only when both inputs (A and B) are HIGH (Y = A • B).
Application Circuit Guide
A typical application for the MC74HC08ADG is as a gating signal or an enable circuit. For instance, it can be used to allow a clock signal to pass only when a specific control line is asserted HIGH.
Basic Gating Circuit:
1. Connect VCC (Pin 14) to the positive rail of your power supply (e.g., 5V).
2. Connect GND (Pin 7) to the common ground.
3. Connect a clock signal (e.g., from a microcontroller or oscillator) to one input of an AND gate (e.g., Pin 1).
4. Connect a control signal (an enable/disable signal) to the other input of the same gate (e.g., Pin 2).
5. The output (Pin 3) will now mirror the clock signal only when the control signal is logic HIGH. When the control is LOW, the output remains permanently LOW.
This simple circuit is the building block for more complex functions like data multiplexing, address decoding, and creating control logic in microprocessor or microcontroller-based systems. Decoupling capacitors (e.g., a 100nF ceramic capacitor placed close to the VCC and GND pins) are highly recommended to suppress power supply noise and ensure stable operation.
ICGOODFIND: The onsemi MC74HC08ADG stands out as a highly reliable and efficient solution for implementing fundamental AND logic operations. Its excellent balance of speed, low power, and noise immunity makes it an indispensable component for both novice electronics enthusiasts and professional engineers designing everything from simple logic circuits to complex digital systems.
Keywords: AND Gate, CMOS Logic, Digital IC, Pinout, Application Circuit
