Part A
74HC02D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 1347 PCS
- Package
- SOIC-14
- Series
- Lógica - Gates e Inverters
Replacement verdict
Not a drop-in replacement
The 74HC02D and 74HC05D are not functionally interchangeable despite sharing the same 74HC logic family and SOIC-14 package. The 74HC02D is a quad 2-input NOR gate with standard push-pull CMOS outputs, while the 74HC05D is a hex inverter with open-drain outputs. The differences in logic function, channel count, output configuration, and the external pull-up requirement of the 74HC05D make direct substitution impossible without circuit redesign.
Different logic function
Different channel count
Different output type
External pull-up may be required
Parts at a glance
Part B
74HC05D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 3327 PCS
- Package
- SOIC-16
- Series
- Lógica - Gates e Inverters
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC02D | 74HC05D | Why it matters |
|---|---|---|---|
| Logic Function | Quad 2-input NOR gate | Hex inverter with open-drain outputs | Defines the fundamental logic operation; these devices are not functionally interchangeable. |
| Number of Gates | 4 | 6 | Determines how many independent logic functions can be implemented per package. |
| Number of Inputs per Gate | 2 | 1 | Affects the logic complexity each gate can handle. |
| Output Type | Push-pull (totem-pole) CMOS | Open-drain | Open-drain outputs require external pull-up resistors and allow wired-OR configurations, while push-pull drives both high and low. |
| Output Drive Capability | ±4 mA (standard HC) | ±4 mA (sink only, open-drain) | Determines the load the output can drive; open-drain only sinks current. |
| Propagation Delay (typical at 5 V) | ~9 ns | ~11 ns | Affects maximum operating frequency and timing margins in digital circuits. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Defines compatible power supply rails for the logic family. |
| Package | SO14 (D suffix) | SO14 (D suffix) | Physical footprint and pin count must match for board-level substitution. |
| Pin Count | 14 | 14 | Pin count must match for package compatibility, though pinout functions differ. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Ensures reliable operation across industrial temperature environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC02D | 74HC05D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | NOR Gate | Inverter |
| Number of Circuits | 4 | 6 |
| Number of Inputs | 2 | 1 |
| Features | - | Open Drain |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Current - Quiescent (Max) | 1 µA | 1 µA |
| Current - Output High Low | 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 | 15ns @ 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 74HC02D and the 74HC05D?
The 74HC02D contains four independent 2-input NOR gates with standard push-pull outputs. The 74HC05D contains six independent inverters with open-drain outputs. They differ in logic function, gate count, and output stage configuration.
Can the 74HC02D and 74HC05D be used interchangeably in a circuit design?
No. The 74HC02D provides a NOR logic function with active push-pull outputs, while the 74HC05D provides an inverting function with open-drain outputs. The logic function, channel count, and output drive characteristics are different, so they are not direct substitutes.
What is the difference in output drive capability between the 74HC02D and the 74HC05D?
The 74HC02D has standard CMOS push-pull outputs that can source and sink current. The 74HC05D has open-drain outputs that can only sink current when the output transistor is on; a pull-up resistor is required to establish a high logic level. Exact drive currents should be verified from the respective manufacturer datasheets.
How do the package and pin configurations of the 74HC02D and 74HC05D compare?
Both devices are commonly offered in a 14-pin SOIC package (the "D" suffix typically denotes SOIC). However, the pin assignments differ because the 74HC02D contains four 2-input NOR gates and the 74HC05D contains six inverters. Pin functions and supply pin locations should be confirmed from the specific manufacturer datasheet before layout or replacement.
Are the 74HC02D and 74HC05D compatible with the same supply voltage range?
Both are 74HC-series CMOS logic devices and are typically specified for a supply voltage range of 2.0 V to 6.0 V. Actual recommended operating conditions, including minimum and maximum supply voltages, should be verified from the manufacturer datasheet for each specific part number.
When should the 74HC05D be chosen instead of the 74HC02D?
The 74HC05D is appropriate when an inverting function with open-drain outputs is required, such as for wired-OR/wired-AND logic, level shifting, or driving loads that require a pull-up to a different voltage. The 74HC02D is appropriate when a 2-input NOR function with standard push-pull outputs is needed.
Do the 74HC02D and 74HC05D have the same input threshold and noise immunity characteristics?
Both devices belong to the 74HC logic family and generally share similar CMOS input threshold ratios and noise immunity specifications. However, exact input threshold voltages, hysteresis, and noise margin values should be confirmed from the manufacturer datasheet for each device, as they may vary by manufacturer and operating conditions.