Part A
74HC574D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 3287 PCS
- Package
- SOIC-20
- Series
- Lógica - Flip Flops
Replacement verdict
Not a drop-in replacement
The 74HC541D octal buffer/line driver and the 74HC574D octal D-type flip-flop are not functionally interchangeable. Although both share the same 20-pin SOIC footprint and 74HC CMOS logic family, their core functions differ fundamentally: the 74HC541D provides combinational non-inverting buffering with 3-state outputs, while the 74HC574D provides edge-triggered D-type storage with 3-state outputs. Substitution would require a complete redesign of the surrounding logic and timing architecture.
Different logic function
Different output type
Different input type
Different timing behavior
Parts at a glance
Part B
74HC541D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 5041 PCS
- Package
- SOIC-20
- Series
- Lógica - Buffers, Drivers, Receivers, Transceivers
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 | 74HC574D | Why it matters |
|---|---|---|---|
| Logic Function | Octal buffer/line driver with 3-state outputs | Octal D-type flip-flop with 3-state outputs | Determines the fundamental behavior: the 74HC541D passes signals combinationally, while the 74HC574D latches data on a clock edge, so they are not functionally interchangeable. |
| Output Type | 3-state, non-inverting | 3-state, non-inverting | Both can drive a shared bus, but the 74HC574D only updates its outputs on a clock edge, affecting timing and control architecture. |
| Number of Flip-Flops | 0 | 8 | The presence of eight edge-triggered flip-flops in the 74HC574D enables synchronous data storage, which the 74HC541D cannot provide. |
| Clock Input | None | Yes (CP) | A clock input allows the 74HC574D to capture data synchronously; the 74HC541D has no clock and operates purely combinationally. |
| Output Enable Control | Two active-low OE pins (OE1, OE2) | One active-low OE pin | Different enable configurations affect how the devices are gated onto a bus and how many control lines the system must provide. |
| Propagation Delay (typical) | ~13 ns at 4.5 V | ~20 ns at 4.5 V (clock to output) | Timing differences influence maximum operating frequency and setup/hold requirements in synchronous designs. |
| Input Capacitance | ~3.5 pF | ~3.5 pF | Similar input capacitance means comparable loading on the driving source, but the functional difference still prevents direct substitution. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Both support the same HC-family supply range, so power-supply compatibility is not a limiting factor for substitution. |
| Package | SO16 (D) | SO16 (D) | Identical package and pin count allow the same PCB footprint, but pin functions differ, so a board redesign is still required. |
| Pin Count | 16 | 16 | Same pin count simplifies mechanical compatibility, but the electrical pin assignments are not interchangeable. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC574D | 74HC541D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Function | Standard | - |
| Type | D-Type | - |
| Output Type | Tri-State, Non-Inverted | 3-State |
| Number of Elements | 1 | 1 |
| Number of Bits per Element | 8 | 8 |
| Clock Frequency | 59 MHz | - |
| Max Propagation Delay @ V Max CL | 33ns @ 6V, 150pF | - |
| Trigger Type | Positive Edge | - |
| Current - Output High Low | 7.8mA, 7.8mA | 7.8mA, 7.8mA |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Current - Quiescent (Iq) | 4 µA | - |
| Input Capacitance | 5 pF | - |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Logic Type | - | Buffer, Non-Inverting |
Frequently asked questions
What are the primary functional differences between the 74HC541D and the 74HC574D?
The 74HC541D is an octal non-inverting buffer/line driver with 3-state outputs, while the 74HC574D is an octal D-type flip-flop with 3-state outputs. The 74HC541D passes input signals to the outputs combinationally when enabled, whereas the 74HC574D latches input data on a low-to-high clock transition and presents it at the outputs when enabled.
Are the 74HC541D and 74HC574D pin-compatible in the SOIC-20 package?
No. Although both devices are offered in a 20-pin SOIC package, their pin functions differ. The 74HC541D uses pins for output enable controls (OE1 and OE2) and has no clock pin, while the 74HC574D uses a clock input (CP) and a single output enable (OE). Therefore, they are not direct pin-to-pin replacements.
Can the 74HC541D and 74HC574D be used interchangeably in a design?
No. The 74HC541D is a combinational buffer, and the 74HC574D is a clocked register. Substituting one for the other would change the timing and logic behavior of the circuit. Interchangeability is only possible if the system design accounts for the different control signals and data latching requirements.
What are the output drive capabilities of the 74HC541D and 74HC574D?
Both devices are part of the 74HC family and typically provide standard CMOS output drive. Verified datasheets from manufacturers such as Nexperia, Texas Instruments, and ON Semiconductor specify symmetrical output drive currents, commonly ±6 mA at 5 V, though exact values should be confirmed on the specific manufacturer datasheet.
Do both the 74HC541D and 74HC574D have 3-state outputs?
Yes. Both the 74HC541D and 74HC574D feature 3-state outputs, allowing the outputs to be placed in a high-impedance state. This enables bus-oriented applications where multiple devices share a common data line.
What is the difference in control inputs between the 74HC541D and 74HC574D?
The 74HC541D has two active-low output enable inputs (OE1 and OE2) that control the 3-state outputs. The 74HC574D has a single active-low output enable (OE) and a clock input (CP) that triggers data latching on the rising edge. The 74HC541D has no clock input.
Which device is more suitable for capturing and holding data, the 74HC541D or the 74HC574D?
The 74HC574D is more suitable for capturing and holding data because it is a D-type flip-flop that latches input data on a clock edge and retains it until the next clock pulse. The 74HC541D does not store data; its outputs follow its inputs continuously when enabled.
Are the 74HC541D and 74HC574D available in identical package options?
Both devices are commonly available in SOIC-20, TSSOP-20, and other standard 20-pin packages from various manufacturers. However, package availability may vary by manufacturer and distributor. Always verify the specific orderable part number and package suffix before design commitment.