74HC02 Quad 2-Input NOR Gate: Datasheet, Pinout, and Circuit

In digital electronics, the 74HC02 Quad 2-Input NOR Gate is a cornerstone for countless applications, providing designers with a versatile and efficient building block. This integrated circuit (IC) belongs to the 74HC series, renowned for its high-speed operation, low power consumption, and compatibility with various logic families. In this article, we will explore the 74HC02 datasheet, pinout, features, circuit, and applications, you'll discover the functionality of the 74HC02 IC and how to integrate it into a circuit.

What is 74HC02?

The 74HC02 is a quad 2-input NOR gate. It incorporates clamp diodes on its inputs, allowing the utilization of current-limiting resistors for interfacing inputs with voltages surpassing VCC. The 74HC02 is a member of the 74HC family, which integrates four independent 2-input NOR gates into a single package. Each NOR gate, a fundamental logic gate, produces a high output only when both inputs are low. This simple yet powerful functionality makes the 74HC02 an indispensable component in digital circuits, enabling the creation of diverse logic functions.

Feature & Specifications

Features

• Wide operating voltage range: 2.0 V to 6.0 V

• Low power dissipation with CMOS technology

• High noise immunity

• Robust latch-up performance exceeding 100 mA per JESD 78 Class II Level B

• nput levels:

      For 74HC02: CMOS level

      For 74HCT02: TTL level

• Compliance with JEDEC standards:

      JESD8C (2.7 V to 3.6 V)

      JESD7A (2.0 V to 6.0 V)

• ESD protection:

      HBM JESD22-A114F exceeds 2000 V

      MM JESD22-A115-A exceeds 200 V

• Various package options available

• Specifications provided for temperature ranges of -40 °C to +85 °C and -40 °C to +125 °C

Specifications

Type	Parameter
Max Power Dissipation	500mW
Propagation Delay	15 ns
Quiescent Current	2μA
Turn On Delay Time	7 ns
Logic Level - Low	0.5V ~ 1.8V
Logic Level - High	1.5V ~ 4.2V
Current - Output High, Low	5.2mA 5.2mA
Output Current	25mA
Number of Functions	4

What is the use of 74HC02?

The 74HC02 provides four individual NOR gates. A NOR gate produces an output of 1 (HIGH) only when all its inputs are 0 (LOW). Refer to the truth table below for the corresponding output based on different input scenarios:

How to use 74HC02 Chip?

Like other chips in the 7400 series, this IC requires a power connection before utilization. Most 7400 ICs operate with a VCC voltage of 5V. A distinguishing factor between the HC and LS versions is that the 74HC02 accommodates a range of 2V to 6V, whereas the 74LS02 is limited to 5V.

Once properly connected, you can utilize any of the four basic NOR gates it houses.

The 74HC02 IC connected to power

The current capacity for each output varies depending on the specific chip.

74HC02: When powered with 5V, each NOR gate output of the 74HC08 can either sink or source 4 mA.

74HC02 Pinout

The 74HC02 is equipped with 14 pins and incorporates four fundamental NOR gates, arranged as illustrated in the pinout diagram provided:

The following is the pin description of 74HC02 IC:

Pin No.	Pin Name	Type	Description
1	1Y	Output	Output from the first NOR gate.
2	1A	Input	Input to the first NOR gate.
3	1B	Input	Input to the first NOR gate.
4	2Y	Output	Output from the second NOR gate.
5	2A	Input	Input to the second NOR gate.
6	2B	Input	Input to the second NOR gate.
7	GND	Power	Connect to ground.
8	3A	Input	Input to the third NOR gate.
9	3B	Input	Input to the third NOR gate.
10	3Y	Output	Output from the third NOR gate.
11	4A	Input	Input to the fourth NOR gate.
12	4B	Input	Input to the fourth NOR gate.
13	4Y	Output	Output from the fourth NOR gate.
14	Vcc	Power	Positive power supply. Connect to +5V power.

74HC02 CAD Model

Symbol

Footprint

CAD Model

74HC02 Circuit

Functional Diagram

Test Circuit

74HC02 Circuit Example

Here's a straightforward project employing the 74×02 IC. The NOR gates form an SR latch, retaining the last output value. It governs an LED that you can activate by pressing the On button. Once activated, the LED remains on even after releasing the button. To deactivate the LED, press the Off button.

To assemble this circuit, you'll require the following components:

• 1 x 74HC02

• 1 x LED (L1)

• 2 x 10 kΩ resistor (R1-R2)

• 1 x 1 kΩ resistor (R3)

• 2 x pushbutton (S1-S2)

74HC02 Alternatives & Equivalents

The 74HC02 chip is available in various versions, each maintaining the same functionality but differing in specifications, such as supported voltages and maximum current output.

Here's a compilation of several equivalents of this chip:

• 74HCT02 (High-speed CMOS, TTL compatible)

• 74LS02 (High-speed TTL)

• 74LVC02 (Low Voltage TTL)

• 74AC02 (Advanced CMOS)

• 74ALS02 (Advanced Low-Power Schottky TTL)

• 74F02 (Very High Speed)

• 74C02 (CMOS, akin to the 4000-series)

74HC02 Application

The 74HC02 is widely applied in diverse digital circuit configurations, encompassing:

• Logic Gates: Integrate multiple 74HC02 ICs to craft fundamental logic gates like XOR, XNOR, AND, and OR, forming the backbone of digital systems.

• Flip-Flops and Latches: Construct memory components such as flip-flops and latches utilizing NOR gates.

• Arithmetic Circuits: Implement adders and subtractors within arithmetic circuits.

• Data Encoders and Decoders: Employ NOR gates for data encoding and decoding functions.

Moreover, its utility extends to various applications, including:

• Industrial Automation: Interface with diverse sensors and actuators.

• Automotive: Employed in power electronic designs.

• Mobile: Integrated into power electronic designs.

• Consumer Electronics: Incorporated in power electronic designs.

Maximum Ratings

Symbol	Parameter	Value	Unit
Vcc	DC Supply Voltage (Referenced to GND)	– 0.5 to + 7.0	V
Vin	DC Input Voltage (Referenced to GND)	– 0.5 to VCC + 0.5	V
Vout	DC Output Voltage (Referenced to GND)	– 0.5 to VCC + 0.5	V
lin	DC Input Current, per Pin	±20	mA
Iout	DC Output Current, per Pin	±25	mA
Icc	DC Supply Current, VCC and GND Pins	±50	mA
PD	Power Dissipation in Still Air, SOIC Package† TSSOP Package†	500 450	mW
Tstg	Storage Temperature	– 65 to + 150 ℃	℃
TL	Lead Temperature, 1 mm from Case for 10 Seconds SOIC or TSSOP Packag	260	℃

Recommended Operating Conditions

Symbol	Parameter	Min	Max	Unit
Vcc	DC Supply Voltage (Referenced to GND)	2.0	6.0	V
Vin, Vout	DC Input Voltage, Output Voltage (Referenced to GND)	0	Vcc	V
TA	Operating Temperature, All Package Type	-55	+125	℃
tr, tf	Input Rise and Fall Time (74HC02 waveforms figure) Vcc = 2.0 V Vcc = 4.5 V Vcc = 6.0 V	0 0 0	1000 500 400	ns

74HC02 Waveforms

74HC02 Datasheet

Download 74HC02 Datasheet PDF.

Read More

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• The Ultimate Guide to 74ls vs. 74hc series ICs

• The Ultimate Guide to Implementing NOR Gate from NAND Gate

• Exploring NAND, AND, NOR, OR Gate: A Deep Dive into Basic Logic Gates

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