Part A
74HC03D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 3334 PCS
- Package
- SOIC-14
- Series
- Lógica - Gates e Inverters
Replacement verdict
Not a drop-in replacement
The 74HC03D and 74HC05D are not functionally interchangeable despite sharing the same 14-pin SOIC package and 74HC logic family. The 74HC03D provides four 2-input NAND gates with open-drain outputs, while the 74HC05D contains six single-input inverters with open-drain outputs. The differing gate count, logic function, and input configuration prevent direct substitution in existing circuit designs without schematic modification.
Different logic function
Different gate count
Different input configuration
Different pinout assignment
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 | 74HC03D | 74HC05D | Why it matters |
|---|---|---|---|
| Logic Function | Quad 2-input NAND gate with open-drain outputs | Hex inverter with open-drain outputs | Determines the fundamental logic operation; NAND vs inverter means they are not functionally interchangeable in a circuit. |
| Number of Gates | 4 | 6 | Affects how many independent logic functions can be implemented per package. |
| Number of Inputs per Gate | 2 | 1 | Defines the logic capability of each gate; a 2-input NAND cannot be replaced by a single-input inverter. |
| Output Type | Open-drain | Open-drain | Open-drain outputs allow wired-OR/wired-AND connections and level shifting with an external pull-up resistor. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | Defines the compatible power supply voltages for the device in a given system. |
| Propagation Delay (typical at 5 V) | ~9 ns | ~9 ns | Impacts maximum operating frequency and timing margins in synchronous designs. |
| Output Drive Current (IOL) | 4 mA | 4 mA | Determines the ability to sink current when driving loads or wired-OR buses. |
| Package | SO14 | SO14 | Same package footprint allows drop-in board-level compatibility for layout purposes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Ensures reliable operation across industrial and automotive temperature environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC03D | 74HC05D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | NAND Gate | Inverter |
| Number of Circuits | 4 | 6 |
| Number of Inputs | 2 | 1 |
| Features | Open Drain | Open Drain |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Current - Quiescent (Max) | 1 µA | 1 µA |
| Current - Output High Low | -, 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 | 13ns @ 6V, 50pF | 15ns @ 6V, 50pF |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What is the main functional difference between the 74HC03D and 74HC05D?
The 74HC03D contains four 2-input NAND gates with open-drain outputs, while the 74HC05D contains six inverters with open-drain outputs. The 74HC03D provides logic inversion and NAND operation, whereas the 74HC05D provides only logic inversion, both with open-drain output stages.
Are the 74HC03D and 74HC05D pin-compatible?
No. The 74HC03D is typically supplied in a 14-pin SOIC package with four 2-input NAND gates, while the 74HC05D is typically supplied in a 14-pin SOIC package with six inverters. Although both may use the same package footprint, the internal gate count and pin assignments differ, so they are not direct pin-to-pin replacements.
Can the 74HC03D and 74HC05D be used interchangeably in a design?
No. The 74HC03D performs NAND logic with open-drain outputs, while the 74HC05D performs inverter logic with open-drain outputs. Substitution requires verifying the logic function, number of gates, pinout, and output drive characteristics against the target design requirements.
What are the output drive capabilities of the 74HC03D and 74HC05D?
Both devices feature open-drain outputs. In the 74HC series, open-drain outputs typically sink current to ground when active and require an external pull-up resistor to achieve a high logic level. The exact sink current rating should be verified from the specific manufacturer datasheet, as it may vary by supplier and operating conditions.
What supply voltage range do the 74HC03D and 74HC05D support?
Both the 74HC03D and 74HC05D are 74HC-series CMOS devices and typically operate over a supply voltage range of 2.0 V to 6.0 V. Designers should confirm the exact recommended operating conditions from the manufacturer datasheet for the specific part number and package.
Why do the 74HC03D and 74HC05D require pull-up resistors?
Both devices have open-drain outputs, meaning the output transistor can only pull the signal low. To achieve a valid high logic level, an external pull-up resistor connected to the desired logic supply voltage is required. Without a pull-up resistor, the output remains floating when the transistor is off.
What are typical applications for the 74HC03D and 74HC05D?
The 74HC03D is commonly used for wired-AND logic, level shifting, and driving loads that require open-drain outputs with NAND logic. The 74HC05D is commonly used for signal inversion, level shifting, and interfacing with buses or loads where open-drain inverters are needed. Both are suitable for mixed-voltage logic interfacing when used with appropriate pull-up resistors.
Do the 74HC03D and 74HC05D have the same propagation delay?
Propagation delay can differ between the two devices due to differences in internal gate topology and the number of gates. The 74HC03D and 74HC05D may have similar but not identical propagation delay specifications. The exact values should be obtained from the respective manufacturer datasheets for the specific part and test conditions.