Part A
74HC125D
Toshiba Halbleiter und Speicher
- Lifecycle
- Active
- Stock
- 3803 Stückzahl
- Package
- SOIC-14
- Series
- Logic c Puffer, Treiber, Empfänger, Transceiver
Replacement verdict
Not a drop-in replacement
The 74HC125D and 74HC14D,653 are not functionally interchangeable despite sharing the 74HC logic family and SO14 package. The 74HC125D provides four independent non-inverting tri-state buffers with active-LOW output enable control, while the 74HC14D,653 provides six inverting Schmitt-trigger inputs without tri-state capability. The differences in logic function, channel count, output drive configuration, and input threshold behavior make direct substitution impossible without circuit redesign.
Different logic function
Different channel count
Different output type
Different input threshold
Parts at a glance
Part B
74HC14D,653
Nexperia USA Inc.
- Lifecycle
- Active
- Stock
- 3794 Stückzahl
- Package
- SOIC-14
- Series
- Logic-Gates und Wechselrichter
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC125D | 74HC14D,653 | Why it matters |
|---|---|---|---|
| Logic Function | Quad Buffer/Line Driver with 3-state outputs | Hex Inverting Schmitt Trigger | Defines the fundamental signal-processing behavior; these devices are not functionally interchangeable. |
| Number of Channels | 4 | 6 | Determines how many independent signal lines can be handled by a single package. |
| Output Type | 3-state | Push-pull (inverting) | 3-state outputs allow bus sharing, while push-pull outputs cannot be tied together without contention. |
| Input Type | Standard CMOS | Schmitt trigger | Schmitt trigger inputs provide hysteresis for noisy or slow-rising signals, which standard inputs do not. |
| Enable/Control | Active-low output enable per channel | None | Output enable pins allow high-impedance state control for multiplexed buses; the inverter has no such control. |
| Propagation Delay (typical at 5 V) | ~14 ns | ~13 ns | Affects timing margins in high-speed digital circuits. |
| Output Drive Current | ±6 mA | ±5.2 mA | Determines fan-out and ability to drive loads such as LEDs or long traces. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both support standard HC-family supply rails, enabling use in 3.3 V and 5 V systems. |
| Package | SO14 | SO14 | Identical footprint allows drop-in PCB compatibility without layout changes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Both are suitable for industrial and automotive-grade environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC125D | 74HC14D,653 |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | Buffer, Non-Inverting | Inverter |
| Number of Circuits | - | 6 |
| Number of Inputs | - | 1 |
| Features | - | Schmitt Trigger |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Current - Quiescent (Max) | - | 2 µA |
| Current - Output High Low | 7.8mA, 7.8mA | 5.2mA, 5.2mA |
| Logic Level - Low | - | 0.3V ~ 1.2V |
| Logic Level - High | - | 1.5V ~ 4.2V |
| Max Propagation Delay @ V Max CL | - | 21ns @ 6V, 50pF |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Number of Elements | 4 | - |
| Number of Bits per Element | 1 | - |
| Output Type | 3-State | - |
Frequently asked questions
What are the main functional differences between the 74HC125D and the 74HC14D,653?
The 74HC125D contains four independent non-inverting buffers with 3-state outputs, while the 74HC14D,653 contains six independent inverting Schmitt-trigger buffers. The 74HC125D is used for bus driving and signal buffering with high-impedance output capability, whereas the 74HC14D,653 is used for signal conditioning, waveform shaping, and noise rejection on slowly changing or noisy inputs.
Are the 74HC125D and 74HC14D,653 pin-compatible?
No. The 74HC125D is typically supplied in a 14-pin SOIC package with four buffers, each having an independent output enable pin. The 74HC14D,653 is supplied in a 14-pin SOIC package with six inverters and no output enable pins. Although both may use the same package footprint, the pin functions and internal channel count differ, so they are not direct pin-to-pin replacements.
Can the 74HC125D drive a bus while the 74HC14D,653 cannot?
Yes. The 74HC125D features 3-state outputs that can be placed in a high-impedance state via its output enable pins, making it suitable for bidirectional bus and multiplexed signal applications. The 74HC14D,653 has standard push-pull outputs without 3-state capability, so it cannot share a bus line with other active drivers without external isolation.
Which device is better for cleaning up noisy or slow digital signals?
The 74HC14D,653 is better suited for signal conditioning because each of its six inverters has Schmitt-trigger inputs with defined positive and negative threshold voltages. This hysteresis rejects noise and produces sharp output transitions from slow or distorted input waveforms. The 74HC125D has standard CMOS input thresholds and does not provide Schmitt-trigger hysteresis.
Do both devices operate from the same supply voltage range?
Yes. Both the 74HC125D and the 74HC14D,653 are 74HC-family CMOS devices and are specified for a nominal supply voltage range of 2.0 V to 6.0 V. Electrical parameters such as propagation delay, output drive, and input threshold voltages vary with supply voltage and must be checked against the respective manufacturer datasheet for the target operating conditions.
How do the output drive capabilities compare between the 74HC125D and the 74HC14D,653?
Both devices are 74HC-family parts and typically provide symmetrical CMOS output drive in the range of ±4 mA to ±6 mA at 4.5 V, depending on the specific manufacturer and test conditions. Neither device is intended for high-current loads. For exact output current ratings, the applicable manufacturer datasheet for each part number must be consulted.
Can the 74HC125D and 74HC14D,653 be used interchangeably in an existing design?
No. They differ in logic function, channel count, output type, and input threshold behavior. The 74HC125D provides four non-inverting 3-state buffers, while the 74HC14D,653 provides six inverting Schmitt-trigger buffers. Substitution requires a full review of logic polarity, bus control, input signal characteristics, and PCB pin assignments.
Are the 74HC125D and 74HC14D,653 available in the same package type?
Both part numbers are commonly available in a 14-pin SOIC package, which is indicated by the D suffix in the 74HC125D and the D,653 suffix in the 74HC14D,653. However, identical package type does not imply identical pinout or electrical function. Designers must verify the pin configuration and package drawing from the manufacturer datasheet before layout or replacement.