74HC02 Quad 2-Input NOR Logic Gate IC
= High-Speed CMOS NOR Gate for Digital Logic and Control Applications =
The 74HC02 is a highspeed CMOS logic IC featuring four independent 2input NOR gates. The NOR gate produces a HIGH output only when ALL inputs are LOW, and a LOW output when any input is HIGH. This fundamental logic function is essential for active-low enable circuits, logic inversion, signal gating, and combinational logic implementations.
Operating voltage range: 2.0V to 6.0V
Propagation delay: 8ns typical at 5V
Output drive capability: ±5.2mA at 6V
Do not exceed 7.0V supply voltage - permanent damage may occur
Unused inputs must be tied to VCC or GND - floating inputs can cause excessive power consumption and oscillation
= Technical Specifications =
| Parameter | Value |
|---|
| Supply Voltage (VCC) | 2.0V to 6.0V |
| Input Voltage | 0V to VCC |
| Output Current (High/Low) | ±5.2mA (at 6V) |
| Propagation Delay | 8ns typical at 5V |
| Quiescent Current | 2µA typical (at 6V) |
| Operating Temperature | -40°C to +125°C |
| Package Types | DIP14, SOIC14, TSSOP-14 |
| Number of Gates | 4 (2-input each) |
= Pin Configuration (DIP14/SOIC14/TSSOP-14) =
| Pin | Name | Function |
|---|
| 1 | 1Y | Gate 1 Output |
| 2 | 1A | Gate 1 Input A |
| 3 | 1B | Gate 1 Input B |
| 4 | 2Y | Gate 2 Output |
| 5 | 2A | Gate 2 Input A |
| 6 | 2B | Gate 2 Input B |
| 7 | GND | Ground (0V) |
| 8 | 3Y | Gate 3 Output |
| 9 | 3A | Gate 3 Input A |
| 10 | 3B | Gate 3 Input B |
| 11 | 4Y | Gate 4 Output |
| 12 | 4A | Gate 4 Input A |
| 13 | 4B | Gate 4 Input B |
| 14 | VCC | Supply Voltage (2V to 6V) |
= Truth Table (Per Gate) =
| Input A | Input B | Output Y |
|---|
| LOW | LOW | HIGH |
| LOW | HIGH | LOW |
| HIGH | LOW | LOW |
| HIGH | HIGH | LOW |
NOR gate output is HIGH ONLY when ALL inputs are LOW - otherwise output is LOW
= Key Features =
Four Independent NOR Gates Provides multiple NOR functions in a single 14pin package
Wide Supply Range - Operates from 2V to 6V for flexible system integration
Low Power Consumption 2µA quiescent current ideal for battery-powered designs
High Noise Immunity - VIH/VIL specifications ensure reliable operation
Compatible Inputs - Accepts both CMOS and TTL drive levels
Schmitt Trigger Action - Clean switching even with slow input edges
== Applications ==
- Active-low enable and disable circuits
- Signal inversion and gating
- Logic decision and control systems
- Alarm and monitoring circuits
- Address decoding in memory systems
- Reset and shutdown control
- Industrial automation logic
- Consumer electronics controls
- Boolean equation implementation
- Latch and flip-flop circuits
Versatile NOR Function - Universal gate can implement any logic function
Four Gates in One IC - Saves board space and reduces component count
√ Industry-standard 74HC02 pinout for easy replacement
√ Low power consumption - 2µA typical quiescent current
√ Fully tested and guaranteed functional
= Package Includes =
| 1. *1x* 74HC02 Logic IC (Package | DIP14, SOIC14, or TSSOP-14 per variant) |
- Anti-static packaging for safe delivery
Use NOR gate as an inverter by tying both inputs together
Use NOR gate as active-low AND by applying inverted inputs
This IC is also available as 74HCT02 for TTL-compatible input levels
NOR gate with one input tied LOW acts as a noninverting buffer (passthrough)
NOR gate with one input tied HIGH produces constant LOW output
NOR gate is a universal gate - can be used to build AND, OR, NOT, and NAND functions
Multiple NOR gates can be cascaded for wide-input NOR functions
Never leave inputs floating use pullup or pull-down resistors
ESD sensitive device - use proper handling procedures
Ensure decoupling capacitor (0.1µF) is placed near VCC pin
