Part A
74HC126D
Toshiba Semiconductor và lưu trữ
- Lifecycle
- Active
- Stock
- 7257 PCS
- Package
- SOIC-14
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Not a drop-in replacement
The 74HC126D and 74HC14D,653 are not functionally interchangeable. The 74HC126D is a quad bus buffer with 3-state outputs controlled by active-high enable pins, while the 74HC14D,653 is a hex inverting Schmitt trigger designed for signal conditioning with hysteresis. Their logic functions, channel counts, output structures, and pinouts differ fundamentally, so substituting one for the other is not feasible without redesigning the surrounding circuit.
Different logic function
Different channel count
Different output type
Different pinout
Parts at a glance
Part B
74HC14D,653
Nexperia Hoa Kỳ Inc.
- Lifecycle
- Active
- Stock
- 3794 PCS
- Package
- SOIC-14
- Series
- Logic - Gates and 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 | 74HC126D | 74HC14D,653 | Why it matters |
|---|---|---|---|
| Logic Function | Quad Buffer with 3-State Outputs | Hex Inverter with Schmitt Trigger Inputs | The core logic function determines whether the device buffers or inverts signals, which fundamentally changes circuit behavior and prevents direct substitution. |
| Number of Channels | 4 | 6 | Channel count affects how many independent signal lines can be processed, impacting board layout and available I/O. |
| Output Type | 3-State | Push-Pull | 3-state outputs allow bus sharing and high-impedance disconnection, while push-pull outputs cannot be tied together without contention. |
| Input Type | Standard CMOS | Schmitt Trigger | Schmitt trigger inputs provide hysteresis for noise immunity and slow-edge signal conditioning, which standard CMOS inputs lack. |
| Output Enable Control | Yes (active-high OE per channel) | No | Enable pins allow dynamic control of output impedance states, essential for multiplexed or shared bus architectures. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | Matching supply voltage ranges ensures compatibility with the same power rails and logic levels in a given design. |
| Propagation Delay (typical at 5 V) | ~11 ns | ~11 ns | Similar propagation delays indicate comparable timing performance, which is critical for synchronous and high-speed signal paths. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Identical temperature ranges ensure both parts can be used in the same environmental conditions without derating concerns. |
| Package | SO14 (SOIC-14) | SO14 (SOIC-14) | Package compatibility determines whether the part can be placed on the same PCB footprint without layout changes. |
| Pin Count | 14 | 14 | Matching pin counts suggest similar footprint potential, but pin functions must still be verified for true interchangeability. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC126D | 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 primary functional differences between the 74HC126D and the 74HC14D,653?
The 74HC126D is a quad non-inverting buffer with 3-state outputs, meaning each of its four gates passes the input signal unchanged and can be switched to a high-impedance state via an active-high output enable pin. The 74HC14D,653 is a hex inverting Schmitt trigger, meaning it contains six gates that invert the input signal and include hysteresis for noise-immune processing of slow or noisy edges. They differ in logic function, gate count, output type, and input threshold behavior.
Can the 74HC126D and 74HC14D,653 be used interchangeably in a design?
No. The 74HC126D provides non-inverting 3-state buffering, while the 74HC14D,653 provides inverting Schmitt-trigger action. Their logic polarity, output drive configuration, and input threshold characteristics are different, so a direct substitution would change circuit behavior unless the surrounding design is specifically adapted to the alternate function.
Do the 74HC126D and 74HC14D,653 have the same package and pinout?
Both devices are commonly offered in a 14-pin SOIC package, but their pin functions are not identical. The 74HC126D uses pins for four data inputs, four data outputs, and four output-enable controls. The 74HC14D,653 uses pins for six inputs and six outputs with power and ground pins. Therefore, although the package style may be similar, the pinout and electrical function are not pin-to-pin compatible.
Which device is better for cleaning up noisy or slow digital signals?
The 74HC14D,653 is the appropriate choice for noisy or slow digital signals because it is a Schmitt-trigger device with defined hysteresis. The 74HC126D is a standard non-inverting buffer and does not provide Schmitt-trigger hysteresis, so it is not intended for signal conditioning of slowly changing or noisy inputs.
What is the role of the output enable pin on the 74HC126D compared with the 74HC14D,653?
The 74HC126D includes output enable pins that place each non-inverting buffer output into a high-impedance state when disabled, allowing bus sharing or multiplexed signal routing. The 74HC14D,653 does not have 3-state output enable controls; its outputs are always actively driven according to the Schmitt-trigger input condition.
Are the 74HC126D and 74HC14D,653 both compatible with standard 74HC logic levels?
Yes. Both are members of the 74HC logic family and are specified for standard 74HC input and output voltage levels when operated within the recommended supply voltage range. However, the 74HC14D,653 has Schmitt-trigger input thresholds with hysteresis, while the 74HC126D has standard CMOS input thresholds without hysteresis.
Which device should be selected for bus buffering or bidirectional data-line control?
The 74HC126D is the suitable choice for bus buffering or controlled data-line interfacing because its 3-state outputs can be disabled to release the bus. The 74HC14D,653 is not intended for bus arbitration or high-impedance bus release because it lacks 3-state output capability.
Do the 74HC126D and 74HC14D,653 have the same logic gate count and channel count?
No. The 74HC126D contains four non-inverting buffer channels with 3-state outputs. The 74HC14D,653 contains six inverting Schmitt-trigger channels. The difference in channel count and logic function affects board layout, signal routing, and the number of available gates in a design.