Part A
74HC151D
東芝セミコンダクター・アンド・ストレージ
- Lifecycle
- Active
- Stock
- 3388 個数
- Package
- SOIC-16
- Series
- ロジック - 信号スイッチ、マルチプレクサ、デコーダ
Replacement verdict
Not a drop-in replacement
The 74HC125D and 74HC151D are not functionally interchangeable despite sharing the same 74HC logic family and SOIC-14 package. The 74HC125D is a quad bus buffer with 3-state outputs, while the 74HC151D is an 8-to-1 multiplexer with complementary outputs. Their internal logic functions, pin assignments, and signal routing are fundamentally different, making direct substitution impossible without circuit redesign.
Different logic function
Different output type
Different pin assignment
Different channel count
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 | 74HC151D | Why it matters |
|---|---|---|---|
| Logic Function | Quad Buffer/Line Driver with 3-State Outputs | 8-to-1 Multiplexer/Data Selector | The core logic function determines whether the devices are functionally interchangeable; these are fundamentally different functions and cannot substitute for each other. |
| Number of Channels | 4 | 1 (8 inputs to 1 output) | Channel count affects how many independent signals can be handled, directly impacting circuit design and board layout. |
| Output Type | 3-State | Push-Pull (Standard CMOS) | 3-state outputs allow bus sharing and high-impedance disconnection, while push-pull outputs cannot be tied together without contention. |
| Number of Pins | 14 | 16 | Pin count determines package footprint and PCB layout compatibility; different pin counts are not drop-in replacements. |
| Package Type | SO14 (Small Outline) | SO16 (Small Outline) | Package type and body width must match for physical board compatibility and automated assembly. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | The operating voltage range must be compatible with the rest of the system for reliable logic-level operation. |
| Logic Family | HC (High-Speed CMOS) | HC (High-Speed CMOS) | Same logic family ensures compatible input thresholds, output drive, and switching speeds. |
| Propagation Delay (typical at 5 V) | ~11 ns | ~14 ns | Propagation delay affects maximum operating frequency and timing margins in synchronous designs. |
| Output Drive Current | ±6 mA (at 5 V) | ±5.2 mA (at 5 V) | Drive current determines the ability to drive loads such as LEDs, other logic inputs, or transmission lines. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | The temperature range must cover the application environment for reliable operation. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC151D | 74HC125D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Type | Multiplexer | - |
| Circuit | 1 x 8:1 | - |
| Independent Circuits | 1 | - |
| Current - Output High Low | 5.2mA, 5.2mA | 7.8mA, 7.8mA |
| Voltage Supply Source | Single Supply | - |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Logic Type | - | Buffer, Non-Inverting |
| Number of Elements | - | 4 |
| Number of Bits per Element | - | 1 |
| Output Type | - | 3-State |
Frequently asked questions
What are the primary functions of the 74HC125D and 74HC151D?
The 74HC125D is a quad non-inverting buffer/line driver with 3-state outputs, while the 74HC151D is an 8-input multiplexer with complementary outputs. They serve fundamentally different logic functions and are not interchangeable.
Can the 74HC125D and 74HC151D be used interchangeably in a circuit?
No. The 74HC125D provides four independent 3-state buffers with active-LOW output enable pins, whereas the 74HC151D selects one of eight data inputs based on a 3-bit select code. Their pinouts, logic functions, and applications differ completely.
What are the supply voltage and logic family specifications for both devices?
Both are 74HC-series high-speed CMOS devices typically operating from 2.0 V to 6.0 V, with standard 74HC input thresholds and CMOS output drive characteristics. Verify exact limits in the respective manufacturer datasheets.
What package type do the 74HC125D and 74HC151D use?
Both the 74HC125D and 74HC151D are commonly offered in SO14 (D) packages, a 14-pin small-outline surface-mount package. Always confirm the specific package suffix in the manufacturer ordering information.
How many pins do the 74HC125D and 74HC151D have, and are they pin-compatible?
Both devices are 14-pin ICs, but they are not pin-compatible. The 74HC125D uses pins for four buffer inputs, four 3-state outputs, and enable controls, while the 74HC151D uses pins for eight data inputs, select inputs, and multiplexer outputs.
What are typical applications for the 74HC125D versus the 74HC151D?
The 74HC125D is used for bus driving, signal buffering, and 3-state bus isolation. The 74HC151D is used for data selection, multiplexing, signal routing, and logic function generation from multiple inputs.
Do both devices support 3-state outputs?
Only the 74HC125D features 3-state outputs controlled by active-LOW enable pins. The 74HC151D provides standard push-pull complementary outputs (Y and Y-bar) and does not have a high-impedance output state.
What are the output drive capabilities of the 74HC125D and 74HC151D?
Both are standard 74HC CMOS outputs. Typical 74HC output drive is specified in the manufacturer datasheet, usually around ±4 mA to ±6 mA at 4.5 V, depending on the specific manufacturer and test conditions. Consult the datasheet for exact ratings.