Part A
74HCT00D
Toshiba Halbleiter und Speicher
- Lifecycle
- Active
- Stock
- 1289 Stückzahl
- Package
- SOIC-20
- Series
- Logic-Gates und Wechselrichter
Replacement verdict
Not a drop-in replacement
The 74HCT00D and 74HCT125D-Q100J are not functionally interchangeable. The 74HCT00D is a quad 2-input NAND gate, while the 74HCT125D-Q100J is a quad 3-state non-inverting buffer. They differ in logic function, output type, channel count, and package configuration, so direct substitution is not possible without circuit redesign.
Different logic function
Different output type
Different channel count
Different package type
Parts at a glance
Part B
74HCT125D-Q100J
Nexperia USA Inc.
- Lifecycle
- Active
- Stock
- 9544 Stückzahl
- Package
- SOIC-14
- Series
- Logic c Puffer, Treiber, Empfänger, Transceiver
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HCT00D | 74HCT125D-Q100J | Why it matters |
|---|---|---|---|
| Logic Function | Quad 2-input NAND gate | Quad buffer with 3-state outputs | The logic function determines the boolean operation performed; NAND gates and 3-state buffers are not functionally interchangeable in a circuit. |
| Number of Gates / Channels | 4 | 4 | Both devices contain four independent elements, so the channel count matches even though the function differs. |
| Output Type | Push-pull (totem-pole) | 3-state (tri-state) | 3-state outputs allow bus sharing by high-impedance disconnection, while push-pull outputs cannot be tied together without contention. |
| Number of Inputs per Element | 2 | 1 | Input count per element defines the logic capability; NAND gates require two inputs while buffers accept a single input. |
| Control / Enable Input | None | Yes (active-low output enable per channel) | Enable pins allow dynamic control of output state, which is essential for bus-oriented designs but absent in fixed-function gates. |
| Supply Voltage Range | 4.5 V to 5.5 V | 4.5 V to 5.5 V | Matching supply ranges ensure both parts operate in the same 5 V TTL-compatible systems without level shifting. |
| Logic Family | HCT (High-speed CMOS, TTL-compatible) | HCT (High-speed CMOS, TTL-compatible) | Same logic family guarantees compatible input thresholds and output drive levels for direct interfacing. |
| Qualification Standard | Standard commercial grade | AEC-Q100 qualified (automotive) | AEC-Q100 qualification indicates enhanced reliability and temperature robustness required for automotive applications. |
| Package | SO14 (SOIC-14) | SO14 (SOIC-14) | Package footprint and pin count affect PCB layout and assembly; both use the same 14-pin SOIC outline. |
| Propagation Delay (typical) | ~9 ns at 5 V | ~10 ns at 5 V | Propagation delay influences maximum operating frequency and timing margins in synchronous designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HCT00D | 74HCT125D-Q100J |
|---|---|---|
| Supplier | - | Nexperia USA Inc. |
| Series | 74HCT | Automotive, AEC-Q100, 74HCT |
| Part Status | Obsolete | Active |
| Logic Type | NAND Gate | Buffer, Non-Inverting |
| Number of Elements | - | 4 |
| Number of Bits per Element | - | 1 |
| Output Type | - | 3-State |
| Current - Output High Low | 4mA, 4mA | 6mA, 6mA |
| Voltage - Supply | 4.5V ~ 5.5V | 4.5V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Number of Circuits | 4 | - |
| Number of Inputs | 2 | - |
| Current - Quiescent (Max) | 1 µA | - |
| Logic Level - Low | 0.8V | - |
| Logic Level - High | 2V | - |
| Max Propagation Delay @ V Max CL | 17ns @ 5.5V, 50pF | - |
Frequently asked questions
What are the primary functional differences between the 74HCT00D and the 74HCT125D-Q100J?
The 74HCT00D contains four independent 2-input NAND gates, while the 74HCT125D-Q100J contains four independent non-inverting buffers with 3-state outputs. They perform fundamentally different logic functions and are not pin-to-pin or function-to-function equivalents.
Are the 74HCT00D and 74HCT125D-Q100J pin-compatible?
No. Both use a 14-pin SO package, but their pinouts differ. The 74HCT00D assigns NAND gate inputs and outputs across the pins, whereas the 74HCT125D-Q100J assigns buffer inputs, outputs, and output-enable pins. Direct PCB substitution without layout changes is not possible.
Do both devices operate from the same supply voltage range?
Yes. Both are HCT-family logic devices and are specified for a nominal 5 V supply with a typical operating range of 4.5 V to 5.5 V, consistent with standard 74HCT specifications.
What is the difference in output drive capability between the two parts?
Both devices are specified with standard 74HCT output drive of ±4 mA at 5 V. The 74HCT125D-Q100J adds 3-state control, allowing its outputs to be placed in a high-impedance state, which the 74HCT00D does not support.
Is the 74HCT125D-Q100J qualified for automotive applications while the 74HCT00D is not?
The 74HCT125D-Q100J carries the Q100 suffix, indicating it is qualified to the AEC-Q100 automotive standard. The 74HCT00D, as a standard logic part without the Q100 designation, is not presented as AEC-Q100 qualified.
Can the 74HCT125D-Q100J be used to replace the 74HCT00D in a NAND gate circuit?
No. The 74HCT125D-Q100J is a non-inverting 3-state buffer and cannot perform the logic inversion and NAND function of the 74HCT00D. Replacing one with the other would require redesigning the logic and control circuitry.
Do both devices share the same operating temperature range?
Both are specified for the standard industrial temperature range of −40 °C to +125 °C, which is common for 74HCT-family devices in SO packages.
Which device is more suitable for bus-oriented or multiplexed signal applications?
The 74HCT125D-Q100J is more suitable because its 3-state outputs allow multiple devices to share a common bus by enabling only one output at a time. The 74HCT00D has standard totem-pole outputs and cannot be placed in a high-impedance state.