Part A
74HC595D
東芝セミコンダクター・アンド・ストレージ
- Lifecycle
- Active
- Stock
- 4369 個数
- Package
- SOIC-16
- Series
- ロジック - シフトレジスタ
Replacement verdict
Not a drop-in replacement
The 74HC541D and 74HC595D are not functionally interchangeable despite sharing the same 74HC logic family and SOIC-16 package. The 74HC541D is an octal non-inverting buffer/line driver with 3-state outputs, while the 74HC595D is an 8-bit serial-in/parallel-out shift register with output latches and 3-state outputs. Their internal architectures, pin functions, and control logic differ fundamentally, making direct substitution impossible without a complete circuit redesign.
Different logic function
Different input interface
Different control signals
Different pinout
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74HC541D | 74HC595D | Why it matters |
|---|---|---|---|
| Function | Octal buffer/line driver with 3-state outputs | 8-bit serial-in, serial/parallel-out shift register with output latches and 3-state outputs | Defines the core logic behavior; these devices perform fundamentally different functions and are not direct substitutes. |
| Logic Type | Non-inverting buffer/line driver | Serial-to-parallel shift register | Determines how input data is processed and transferred to outputs, affecting circuit architecture. |
| Number of Outputs | 8 | 8 | Both provide eight outputs, but the data path to those outputs differs significantly. |
| Output Type | 3-state | 3-state | 3-state outputs allow bus sharing, but the control mechanism differs between the two devices. |
| Data Input Interface | Parallel (8 inputs) | Serial (DS, SHCP, STCP) | Parallel input allows simultaneous data capture, while serial input reduces pin count but requires clocked data transfer. |
| Latch/Register | None (direct buffer) | 8-bit shift register plus 8-bit storage latch | The 74HC595D can hold output states while shifting new data, enabling sequential output updates. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both operate over the standard HC-family voltage range, allowing use in similar logic-level systems. |
| Propagation Delay (typical at 5 V) | ~12 ns | ~14 ns (shift) / ~14 ns (latch) | Affects maximum operating frequency and timing margins in high-speed designs. |
| Package | SOIC-20 (D suffix) | SOIC-16 (D suffix) | Different pin counts and footprints prevent direct PCB drop-in replacement. |
| Typical Application | Bus driving, memory address buffering, signal fan-out | LED driving, GPIO expansion, serial-to-parallel data conversion | Highlights the distinct use cases and confirms they are not functionally interchangeable. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC595D | 74HC541D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | Shift Register | Buffer, Non-Inverting |
| Output Type | Tri-State | 3-State |
| Number of Elements | 1 | 1 |
| Number of Bits per Element | 8 | 8 |
| Function | Serial to Parallel, Serial | - |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Current - Output High Low | - | 7.8mA, 7.8mA |
Frequently asked questions
What are the primary functional differences between the 74HC541D and the 74HC595D?
The 74HC541D is an octal non-inverting buffer/line driver with 3-state outputs, designed for signal buffering and bus driving. The 74HC595D is an 8-bit serial-in, parallel-out shift register with a storage register and 3-state output latches, designed for serial-to-parallel data conversion and output expansion.
Can the 74HC541D and 74HC595D be used interchangeably in a design?
No. They have fundamentally different logic functions and pinouts. The 74HC541D provides parallel input to parallel output buffering with an output enable pin, while the 74HC595D accepts serial data input and requires a shift clock, storage clock, and output enable to produce parallel outputs. Direct substitution is not possible without redesigning the circuit and control logic.
What are the package and pin count differences between the 74HC541D and 74HC595D?
Both devices are commonly offered in a 16-pin SOIC package (the "D" suffix typically denotes SOIC). The 74HC541D uses the 16 pins for eight inputs, eight outputs, two output enable pins, and power/ground. The 74HC595D uses the 16 pins for serial input, shift clock, storage clock, output enable, serial output, eight parallel outputs, and power/ground. Pin functions and assignments differ between the two devices.
Which device is suitable for expanding the number of output pins on a microcontroller?
The 74HC595D is suitable for output expansion because it converts serial data from a microcontroller into eight parallel outputs and can be cascaded via its serial output to drive additional 74HC595D devices. The 74HC541D does not perform serial-to-parallel conversion and is used for buffering or driving parallel signals rather than expanding I/O count.
Do both the 74HC541D and 74HC595D have 3-state outputs?
Yes. Both devices feature 3-state outputs that can be placed in a high-impedance state. The 74HC541D controls the 3-state condition through its output enable pins. The 74HC595D controls the 3-state condition through its output enable pin, which affects the parallel outputs.
What are the typical operating voltage and logic family characteristics of the 74HC541D and 74HC595D?
Both devices belong to the 74HC high-speed CMOS logic family and typically operate over a supply voltage range of 2 V to 6 V. They are compatible with standard CMOS logic levels and provide typical propagation delays in the low nanosecond range at 5 V, as specified in manufacturer datasheets.
Which device is better for driving high-current loads such as LEDs or relays?
Both devices have standard CMOS output drive capabilities as specified in their datasheets, typically capable of sourcing or sinking several milliamps per output. Neither device is intended as a high-current driver. For loads requiring higher current than the datasheet ratings, external driver circuitry such as transistors or dedicated driver ICs should be used with either device.
Can the 74HC595D be cascaded to drive more than eight outputs, and can the 74HC541D be cascaded similarly?
The 74HC595D can be cascaded by connecting its serial output to the serial input of another 74HC595D, allowing multiple devices to drive 16, 24, or more outputs from a single serial data stream. The 74HC541D does not have a serial data path and cannot be cascaded in the same manner; multiple 74HC541D devices would require separate parallel input signals and individual output enable control.