Digital logic circuits rely on reliable and efficient components to process signals and perform logical operations. One of the most commonly used devices in CMOS logic design is the CD4011, a quad 2-input NAND gate integrated circuit from the 4000-series logic family. This article will discuss the CD4011 CMOS NAND gate, including its specifications, features, variants, equivalents, and more.

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CD4011 CMOS 2-Input NAND Gate

The CD4011 is a CMOS integrated circuit that contains four independent 2-input NAND gates in one package. It belongs to the 4000-series CMOS logic family, known for low power consumption and stable digital operation. A NAND gate produces a LOW output only when both inputs are HIGH, while all other input combinations produce a HIGH output. Because NAND gates can implement many logic functions, the CD4011 is considered a flexible building block in digital circuits.

The CD4011B is an improved and widely adopted version of the original CD4011. The “B” suffix indicates a refined CMOS design with better electrical performance and manufacturing consistency. Although the logic function and pin configuration remain the same, the CD4011B typically offers improved output drive capability, better noise immunity, and a wider operating voltage range, usually up to 18V.

Today, many manufacturers primarily supply CD4011B, making it the common replacement for the original CD4011 while remaining fully pin-compatible. If you are interested in purchasing the CD4011 or CD4011B, feel free to contact us for pricing and availability.

CAD Models of CD4011

Pinout Details of CD4011

Equivalent Model of CD4011

• HCF4011

• HEF4011

• MC14011

• TC4011

• NTE4011

• 74HC00

• 74HC01

• 74HC03

• CD4093

• CD40107

CD4011 Variants IC

Circuit Diagram of CD4011

The circuit diagram of the CD4011 shows the internal CMOS structure used to implement the quad 2-input NAND gates inside the IC. Each gate is built using a combination of PMOS transistors connected to the positive supply (VDD) and NMOS transistors connected to ground (VSS). The PMOS transistors form the pull-up network, while the NMOS transistors form the pull-down network. This complementary arrangement is typical of CMOS logic and allows the IC to achieve low power consumption and stable switching behavior.

The diagram also shows that two input signals control the transistor pairs inside each NAND gate. When both inputs are HIGH, the NMOS transistors conduct and create a path to ground, pulling the output LOW. If one or both inputs are LOW, the PMOS transistors turn on and pull the output HIGH. This switching behavior produces the NAND logic function, where the output becomes LOW only when both inputs are HIGH.

Another part of the diagram illustrates the input protection network connected to each input pin. These protection diodes help protect the internal CMOS transistors from voltage spikes or electrostatic discharge (ESD). The lower section of the figure also includes a simplified logic diagram, showing how the two inputs pass through an inverter stage and combine to form the NAND output.

Tech Specifications of CD4011

Distinctive Features of CD4011

Low Propagation Delay

The CD4011B provides fast switching performance with a typical propagation delay of about 60 ns when operating at VDD = 10 V with a 50 pF load capacitance. This allows the device to respond quickly to input signal changes and maintain stable logic timing in digital circuits.

Buffered Inputs and Outputs

The IC includes buffered input and output stages, which help improve signal stability and reduce the effect of noise or signal distortion. Buffered stages also allow the logic gate to drive connected components more reliably.

Symmetrical Output Characteristics

The CD4011B is designed with standardized symmetrical output characteristics, meaning the output drive capability is balanced for both HIGH and LOW logic levels. This improves signal consistency across different operating conditions.

Very Low Input Current

The device features an extremely low maximum input current of about 1 µA at 18 V, even across the full operating temperature range. This low input current is a key advantage of CMOS technology and contributes to efficient power usage.

Wide Supply Voltage Capability

The CD4011B supports a wide operating voltage range from 3 V to 18 V, allowing it to work in many different digital systems without requiring complex voltage regulation.

Noise Margin Stability

The IC maintains a strong noise margin over the entire temperature range, improving reliability in environments where electrical noise may affect digital signals.

Fully Tested Quiescent Current

Each CD4011B device is 100% tested for quiescent current at 20 V, ensuring reliable low-power operation and confirming proper CMOS performance.

JEDEC Standard Compliance

The CD4011B meets the requirements of JEDEC Tentative Standard No. 13B, which defines specifications for “B” series CMOS logic devices, ensuring compatibility and standardized electrical characteristics across manufacturers.