Part A
74HC157D
東芝電晶體與存儲
- Lifecycle
- Active
- Stock
- 7197 件
- Package
- SOIC-16
- Series
- 邏輯-訊號開關、多工器、解碼器
Replacement verdict
Not a drop-in replacement
The 74HC157D and 74HC154D,653 are functionally unrelated logic ICs and cannot serve as substitutes for one another. The 74HC157D is a quad 2-to-1 multiplexer, while the 74HC154D,653 is a 4-to-16 line decoder/demultiplexer. Their logic functions, input/output configurations, and pin assignments differ fundamentally, making direct replacement impossible without complete circuit redesign.
Different logic function
Different input/output configuration
Different channel count
Different pin assignment
Parts at a glance
Part B
74HC154D,653
恩智浦美國股份有限公司。
- Lifecycle
- Active
- Stock
- 4133 件
- Package
- SOIC-24
- Series
- 邏輯-訊號開關、多工器、解碼器
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC157D | 74HC154D,653 | Why it matters |
|---|---|---|---|
| Function | Quad 2-input multiplexer | 4-to-16 line decoder/demultiplexer | The logic function is fundamentally different, so these parts are not functionally interchangeable in a circuit. |
| Logic Type | Multiplexer (MUX) | Decoder/Demultiplexer | Determines the signal routing behavior and the role the IC plays in the system. |
| Number of Circuits | 4 | 1 | Affects how many independent signal paths can be handled by a single package. |
| Number of Inputs per Circuit | 2 | 4 | Defines the selection complexity and the number of address lines required. |
| Number of Outputs | 4 | 16 | Determines how many downstream devices or signal lines can be driven. |
| Output Type | 3-State | Active Low | Output polarity and drive style affect compatibility with connected logic and bus structures. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both support common 3.3 V and 5 V logic systems, but this alone does not make them interchangeable. |
| Propagation Delay | Approximately 14 ns at 5 V | Approximately 20 ns at 5 V | Timing differences can affect setup/hold margins and maximum operating frequency. |
| Package | SOIC-16 | SOIC-24 | Different pin counts and footprints prevent direct board-level substitution. |
| Pin Count | 16 | 24 | Pin count mismatch means the devices cannot share the same PCB footprint or socket. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC157D | 74HC154D,653 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Type | Multiplexer | Decoder/Demultiplexer |
| Circuit | 4 x 2:1 | 1 x 4:16 |
| Independent Circuits | 1 | 1 |
| Current - Output High Low | 5.2mA, 5.2mA | 5.2mA, 5.2mA |
| Voltage Supply Source | Single Supply | Single Supply |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the primary functional differences between the 74HC157D and the 74HC154D,653?
The 74HC157D is a quad 2-input multiplexer that selects one of two 4-bit data sources based on a common select input. The 74HC154D,653 is a 4-to-16 line decoder/demultiplexer that decodes a 4-bit binary address into one of 16 mutually exclusive active-LOW outputs. They perform fundamentally different logic functions and are not interchangeable.
Are the 74HC157D and 74HC154D,653 pin-compatible?
No. The 74HC157D is typically supplied in a 16-pin SOIC package, while the 74HC154D,653 is supplied in a 24-pin SOIC package. The pin counts, pin assignments, and package dimensions differ, so they cannot be used as drop-in replacements for each other on the same PCB footprint.
What is the logic family and operating voltage range for both devices?
Both devices belong to the 74HC high-speed CMOS logic family. They are specified for operation over a supply voltage range of 2.0 V to 6.0 V, with typical operation at 5.0 V. This CMOS family provides standard CMOS input thresholds and low power consumption.
Can the 74HC157D be used to drive the 74HC154D,653 in a cascaded design?
Yes, in principle. The 74HC157D can act as a data selector to route address or control signals to the 74HC154D,653 decoder inputs, provided the logic levels, timing, and fan-out requirements are respected. However, the designer must verify that the selected output configuration and active-LOW decoding of the 74HC154D,653 match the system requirements.
What are the output drive capabilities of the 74HC157D and 74HC154D,653?
Both devices are standard 74HC CMOS outputs. They typically provide a symmetric output drive of ±4 mA at 5 V, which is suitable for driving other CMOS inputs or low-power loads. They are not intended for high-current or power-driving applications without external buffering.
How do the propagation delays of the 74HC157D and 74HC154D,653 compare?
Both devices have similar propagation delay characteristics typical of the 74HC family. At a 5 V supply, the typical propagation delay is in the range of 10 ns to 20 ns, depending on the specific input-to-output path and load conditions. The 74HC154D,653 may exhibit slightly different delays due to its more complex internal decoding logic, so the datasheet timing specifications should be consulted for critical timing analysis.
Are the 74HC157D and 74HC154D,653 available in identical package options?
No. The 74HC157D is commonly offered in a 16-pin SOIC package (the "D" suffix typically denotes SOIC). The 74HC154D,653 is offered in a 24-pin SOIC package (the "D" suffix and "653" reel option). Package options may vary by manufacturer, but the two part numbers do not share a common package footprint.
What are the typical applications for each device?
The 74HC157D is typically used for data multiplexing, signal routing, and selecting between two 4-bit data buses. The 74HC154D,653 is typically used for memory address decoding, I/O port selection, and demultiplexing applications where one of 16 outputs must be activated based on a 4-bit address.