Part A
74HC03D
東芝セミコンダクター・アンド・ストレージ
- Lifecycle
- Active
- Stock
- 3334 個数
- Package
- SOIC-14
- Series
- ロジック - ゲートおよびインバータ
Replacement verdict
Not a drop-in replacement
The 74HC04D and 74HC03D are not functionally interchangeable despite sharing the same 14-pin SOIC footprint and 74HC logic family. The 74HC04D provides standard push-pull CMOS outputs, whereas the 74HC03D features open-drain outputs that require external pull-up resistors for proper logic-high operation. This fundamental output architecture difference affects drive capability, power consumption, and PCB design, making direct substitution inadvisable without circuit modification.
Different output type
External pull-up may be required
Different drive current
Different logic function
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 | 74HC03D | Why it matters |
|---|---|---|---|
| Logic Function | Hex inverter (unbuffered output) | Quad 2-input NAND gate with open-drain outputs | The fundamental logic function differs, so the two parts are not functionally interchangeable in a circuit. |
| Number of Gates | 6 | 4 | Gate count affects how many independent logic operations can be performed per package. |
| Number of Inputs per Gate | 1 | 2 | Input count determines the logic operation possible; inverters take one input while NAND gates take two. |
| Output Type | Push-pull (totem-pole) CMOS | Open-drain | Open-drain outputs require external pull-up resistors and allow wired-OR connections, unlike push-pull outputs. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both parts operate over the same supply range, allowing use in similar power environments. |
| Logic Family | 74HC (High-speed CMOS) | 74HC (High-speed CMOS) | Same logic family ensures compatible input/output voltage thresholds and noise margins. |
| Package | SO14 (SOIC-14) | SO14 (SOIC-14) | Identical package allows the same PCB footprint, though pin functions differ. |
| Propagation Delay (typical at 5 V) | ~9 ns | ~10 ns | Slight timing differences can affect high-speed circuit performance and timing margins. |
| Output Drive Capability | ±4 mA (standard CMOS drive) | Sink-only, typically 4 mA; requires external pull-up for high state | Open-drain outputs cannot source current, limiting direct drive of loads that need a high logic level. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC03D | 74HC04D |
|---|---|---|
| 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 | - |
| 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 | 13ns @ 6V, 50pF | 13ns @ 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 74HC04D and the 74HC03D?
The 74HC04D contains six independent inverters with standard push-pull CMOS outputs. The 74HC03D contains four independent 2-input NAND gates with open-drain outputs. The 74HC04D provides both logic inversion and active drive in both HIGH and LOW states, while the 74HC03D requires an external pull-up resistor to establish a defined HIGH level.
Can the 74HC04D and 74HC03D be used interchangeably in a design?
No. They differ in logic function, gate count, output type, and pinout. The 74HC04D is a hex inverter, while the 74HC03D is a quad 2-input NAND gate. The 74HC03D has open-drain outputs that cannot source current, whereas the 74HC04D has push-pull outputs. Direct substitution without redesign is not possible.
What are the output drive characteristics of the 74HC04D?
The 74HC04D provides standard CMOS push-pull outputs. Per the 74HC series specifications, it typically sources or sinks up to 4 mA at 5 V VCC, with symmetrical output drive. It actively drives both logic HIGH and logic LOW levels without requiring external components.
What are the output drive characteristics of the 74HC03D?
The 74HC03D has open-drain N-channel outputs. It can sink current to logic LOW but cannot source current to logic HIGH. A pull-up resistor connected to VCC is required to establish a HIGH level. The sink current capability is typically 4 mA at 5 V VCC, consistent with standard 74HC series specifications.
What is the pin count and package type of the 74HC04D and 74HC03D?
Both the 74HC04D and 74HC03D are typically offered in a 14-pin SOIC package (the "D" suffix denotes SOIC in many manufacturer naming conventions). The 74HC04D uses all 14 pins for six inverters plus VCC and GND. The 74HC03D uses 14 pins for four 2-input NAND gates plus VCC and GND. Pinouts are not identical.
Which device is suitable for wired-OR or wired-AND bus configurations?
The 74HC03D is suitable for wired-AND configurations because its open-drain outputs can be tied together with a single pull-up resistor. The 74HC04D is not suitable for wired-AND or wired-OR configurations because its push-pull outputs cannot be connected together without risking contention and excessive current.
What are the typical propagation delay and operating voltage ranges for these devices?
Both the 74HC04D and 74HC03D operate over a typical VCC range of 2 V to 6 V. At 5 V VCC, the 74HC04D typically exhibits a propagation delay of approximately 8 ns to 15 ns depending on load and manufacturer. The 74HC03D typically exhibits a propagation delay of approximately 10 ns to 18 ns at 5 V VCC. Exact values vary by manufacturer and must be verified against the specific datasheet.
Are the 74HC04D and 74HC03D compatible with 74LS or 74HCT logic levels?
The 74HC04D and 74HC03D are high-speed CMOS devices with CMOS input thresholds, typically 0.7 x VCC for HIGH and 0.3 x VCC for LOW at 5 V. They are generally not directly compatible with 74LS TTL output levels without level shifting. For direct TTL compatibility, 74HCT variants such as 74HCT04D and 74HCT03D should be considered instead.