What is CD4011 NAND Gate IC? Pin Diagram and Applications

The CD4011 is a CMOS integrated circuit containing four independent two-input NAND gates. It is commonly used in digital logic circuits, counters, flip-flops, oscillators, timing circuits, and embedded electronic systems due to its low power consumption and high noise immunity.

Key features of CD4011

• Logic Function: Performs the Boolean NAND function.
• Buffered Outputs: Designed with buffered outputs to improve transfer characteristics by providing very high gain.
• CMOS Construction: Monolithic complementary MOS integrated circuit utilizing N- and P-channel enhancement mode transistors.
• Symmetrical Drive: Equal source and sink current capabilities conforming to standard B series output drive.
• Low Power TTL Compatibility: Can drive up to two 74L loads or one 74LS load directly.
• Wide Operating Voltage: Parametric ratings at 5V, 10V, and 15V (Operating range from 3V to 15V).
• ESD Protection: All inputs are protected against static discharge via internal diodes to Vdd and Vss.
• Low Leakage: Maximum input leakage current of just 1 µA at 15V over the full temperature range.

CD4011 Pin Diagram

Pin Number	Pin Name	Description
1	Input 1A	Data Input A for Gate 1
2	Input 1B	Data Input B for Gate 1
3	Output 1J	NAND Output for Gate 1
4	Output 2J	NAND Output for Gate 2
5	Input 2B	Data Input B for Gate 2
6	Input 2A	Data Input A for Gate 2
7	$V_{SS}$	Ground / Negative Power Supply
8	Input 3A	Data Input A for Gate 3
9	Input 3B	Data Input B for Gate 3
10	Output 3J	NAND Output for Gate 3
11	Output 4J	NAND Output for Gate 4
12	Input 4B	Data Input B for Gate 4
13	Input 4A	Data Input A for Gate 4
14	$V_{DD}$	Positive Power Supply (3V to 15V DC)

Example Use Case : Active-Low SR Latch (Hardware Debouncer)

• Scenario: You need a simple circuit to debounce a physical Single Pole Double Throw (SPDT) switch. Physical switches “bounce” mechanically when flipped, sending dozens of rapid on/off spikes to a microcontroller, which causes errors.

• Solution : Wire two of the independent NAND gates on the CD4011BC to create an Active-Low Set-Reset (SR) Latch.

Applications of CD4011

• Universal Logic Implementation: Because NAND is a “universal gate,” the CD4011 can be used to construct any other type of logic gate (AND, OR, NOT, XOR, etc.).
• Signal Inversion: By connecting both inputs of a single gate together, it functions as a NOT gate (Inverter).
• Astable and Monostable Multivibrators: Commonly used with resistors and capacitors to build simple clock oscillators, timers, and pulse generators.
• CMOS to TTL Bridging: Utilizing its low power TTL compatibility to interface different logic families.

Summary

CD4011 integrates four NAND gates in one package for implementing digital logic functions efficiently.