Part A
74HC02D
Компания Toshiba Semiconductor и Storage
- Lifecycle
- Active
- Stock
- 1347 ПКС
- Package
- SOIC-14
- Series
- Логика - Ворота и инверторы
Replacement verdict
Not a drop-in replacement
The 74HC04D and 74HC02D are not functionally interchangeable despite sharing the same 74HC logic family, SOIC-14 package, and supply voltage range. The 74HC04D provides six independent inverters, while the 74HC02D contains four 2-input NOR gates, resulting in different logic functions, channel counts, and pinout signal assignments. Direct substitution is not possible without circuit redesign.
Different logic function
Different gate count
Different pinout assignment
Different input configuration
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC04D | 74HC02D | Why it matters |
|---|---|---|---|
| Logic Function | Hex Inverter (NOT) | Quad 2-Input NOR Gate | Defines the fundamental logic operation; these are not functionally interchangeable since one inverts and the other performs NOR logic. |
| Number of Gates | 6 | 4 | Determines how many independent logic operations can be performed per package, affecting circuit density and board layout. |
| Number of Inputs per Gate | 1 | 2 | Affects the logic capability of each gate; a NOR gate requires two inputs while an inverter requires only one. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | Both parts share the HC family supply range, allowing operation in 3.3 V and 5 V systems. |
| Output Drive Current | ±4 mA | ±4 mA | Determines the fan-out and ability to drive downstream loads; identical drive simplifies substitution in output stages. |
| Propagation Delay | ~9 ns at 5 V | ~9 ns at 5 V | Affects maximum operating frequency and timing margins in synchronous designs. |
| Package Type | SOIC-14 | SOIC-14 | Same footprint allows drop-in PCB compatibility without layout changes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Ensures both parts meet the same environmental requirements for industrial and automotive applications. |
| Logic Family | 74HC | 74HC | Same family ensures compatible input thresholds and output levels when interfacing with other HC devices. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC02D | 74HC04D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | NOR Gate | Inverter |
| Number of Circuits | 4 | 6 |
| Number of Inputs | 2 | 1 |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Current - Quiescent (Max) | 1 µA | 1 µA |
| Current - Output High Low | 5.2mA, 5.2mA | 5.2mA, 5.2mA |
| Logic Level - Low | 0.5V ~ 1.8V | 0.5V ~ 1.8V |
| Logic Level - High | 1.5V ~ 4.2V | 1.5V ~ 4.2V |
| Max Propagation Delay @ V Max CL | 16ns @ 6V, 50pF | 13ns @ 6V, 50pF |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the primary functional differences between the 74HC04D and 74HC02D?
The 74HC04D contains six independent inverters (NOT gates), while the 74HC02D contains four independent 2-input NOR gates. Both are standard high-speed CMOS logic devices in the 74HC family.
Are the 74HC04D and 74HC02D pin-compatible in the SOIC-14 package?
No. Although both are commonly offered in a 14-pin SOIC package, their pinouts differ. The 74HC04D assigns each of the six inverters to input/output pin pairs, whereas the 74HC02D assigns four NOR gates with shared pin locations for inputs and outputs. They cannot be interchanged without redesigning the PCB layout.
Can the 74HC04D be used as a direct substitute for the 74HC02D in an existing design?
No. The 74HC04D is an inverter and the 74HC02D is a NOR gate. They perform different logic functions and have different pinouts, so a direct substitution is not possible without modifying the circuit design and PCB layout.
What are the typical propagation delay and supply voltage specifications for these devices?
Both the 74HC04D and 74HC02D typically operate over a supply voltage range of 2 V to 6 V. At 5 V and 25 °C, the typical propagation delay is approximately 8 ns to 15 ns depending on the manufacturer and load conditions. Always consult the specific manufacturer datasheet for guaranteed limits.
What is the difference in output drive current between the 74HC04D and 74HC02D?
Both devices are standard 74HC CMOS logic and typically provide symmetrical output drive of ±4 mA at 5 V, with some manufacturers specifying ±5.2 mA. The drive capability is essentially the same for both logic functions under equivalent test conditions.
Which device is better for building an oscillator circuit?
The 74HC04D is commonly used in crystal oscillator and RC oscillator circuits because its inverting function provides the necessary 180° phase shift. The 74HC02D, being a NOR gate, can also be used in oscillator configurations but is less commonly selected for that purpose. The choice depends on the specific circuit topology.
Do the 74HC04D and 74HC02D have the same input and output voltage thresholds?
Yes. As members of the 74HC logic family, both devices share the same DC input and output voltage characteristics, including typical switching thresholds of 0.5 × VCC at 5 V and standard CMOS noise margins. Their logic thresholds are identical when operated at the same supply voltage and temperature.
Are the 74HC04D and 74HC02D available in identical package options?
Both devices are widely available in SOIC-14, TSSOP-14, and DIP-14 packages from multiple manufacturers. However, package availability may vary by manufacturer and distributor, so the specific orderable part number should be verified before design release.