Part A
74HC573D
Toshiba Semiconductor et stockage
- Lifecycle
- Active
- Stock
- 3424 PCS
- Package
- SOIC-14
- Series
- Logique - verrou
Replacement verdict
Not a drop-in replacement
The 74HC541D and 74HC573D are not functionally interchangeable despite sharing the same 74HC CMOS logic family and 20-pin SOIC footprint. The 74HC541D is an octal non-inverting buffer/line driver with 3-state outputs controlled by two active-low output enable pins, while the 74HC573D is an octal D-type transparent latch with 3-state outputs controlled by separate latch enable and output enable pins. The fundamental logic function, control architecture, and pinout differ, so direct substitution is not possible without circuit redesign.
Different logic function
Different control architecture
Different pinout
Different output enable scheme
Parts at a glance
Part B
74HC541D
Toshiba Semiconductor et stockage
- Lifecycle
- Active
- Stock
- 5041 PCS
- Package
- SOIC-20
- Series
- Logique - Buffers, lecteurs, récepteurs, émetteurs - récepteurs
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 | 74HC573D | Why it matters |
|---|---|---|---|
| Logic Function | Octal buffer/line driver with 3-state outputs (non-inverting) | Octal D-type transparent latch with 3-state outputs | Defines the core behavior; a buffer passes signals combinationally while a latch stores data, so they are not functionally interchangeable. |
| Output Type | 3-state, non-inverting | 3-state, non-inverting | Both offer high-impedance bus capability, but the latch adds storage, affecting how the output responds to inputs. |
| Number of Bits | 8 | 8 | Both handle 8-bit wide data, so bus width compatibility is equivalent. |
| Control Inputs | Two active-low output enable pins (OE1, OE2) | Latch enable (LE) and output enable (OE) | Different control schemes mean the driving logic and timing must be redesigned when substituting one for the other. |
| Data Storage | None (combinational) | Transparent D-type latch | The latch can hold data when LE is low, enabling temporary storage that the buffer cannot provide. |
| Propagation Delay (tPD) | Typically ~13 ns at 4.5 V | Typically ~14 ns at 4.5 V | Similar speed, but timing margins must be rechecked because the latch adds setup and hold requirements. |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | Identical supply compatibility allows both to operate in the same HC-family logic systems. |
| Output Drive Current | ±6 mA at 4.5 V | ±6 mA at 4.5 V | Equal drive strength means fan-out and load driving capability are comparable. |
| Package | SOIC-20 (D suffix) | SOIC-20 (D suffix) | Same package and pin count simplify PCB layout, though pin functions differ. |
| Pin Configuration | Inputs on one side, outputs on opposite side | Inputs and outputs on opposite sides with LE/OE control | Pinout differences prevent direct drop-in replacement without board or wiring changes. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC573D | 74HC541D |
|---|---|---|
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | D-Type Latch | Buffer, Non-Inverting |
| Circuit | 8:8 | - |
| Output Type | Tri-State | 3-State |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Independent Circuits | 1 | - |
| Delay Time - Propagation | 26ns | - |
| Current - Output High Low | 7.8mA, 7.8mA | 7.8mA, 7.8mA |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Number of Elements | - | 1 |
| Number of Bits per Element | - | 8 |
Frequently asked questions
What are the primary functional differences between the 74HC541D and the 74HC573D?
The 74HC541D is an octal non-inverting buffer/line driver with 3-state outputs, featuring two active-low output enable pins (OE1 and OE2). The 74HC573D is an octal D-type transparent latch with 3-state outputs, featuring a latch enable (LE) pin and an output enable (OE) pin. The 74HC541D does not have data storage capability, while the 74HC573D can latch and hold data.
Are the 74HC541D and 74HC573D pin-compatible?
No. Both devices use a 20-pin package (SOIC-20 for the D suffix), but the pin functions differ. On the 74HC541D, pins 1 and 19 are output enable inputs. On the 74HC573D, pin 11 is the latch enable input and pin 1 is the output enable input. Pin assignments for inputs and outputs also differ, so they are not drop-in replacements.
Can the 74HC541D be used to replace the 74HC573D in an existing design?
No, not directly. The 74HC541D lacks the transparent latch function of the 74HC573D. If the design requires data storage or latching, the 74HC541D cannot perform that function. Additionally, the pinouts and control signal assignments are different, so PCB layout changes would be required.
What are the output drive capabilities of the 74HC541D and 74HC573D?
Both devices are 74HC series CMOS logic and typically provide symmetrical output drive. Standard 74HC specifications list a output drive current of ±4 mA at 5 V for both the 74HC541D and 74HC573D, though actual values should be confirmed from the specific manufacturer datasheet.
Do both the 74HC541D and 74HC573D have 3-state outputs?
Yes. Both the 74HC541D and 74HC573D feature 3-state outputs that can be placed in a high-impedance state. The 74HC541D uses two active-low output enable pins to control all eight outputs. The 74HC573D uses a single active-low output enable pin to control all eight outputs, independent of the latch function.
What is the difference in control signal behavior between the 74HC541D and 74HC573D?
The 74HC541D has two output enable pins (OE1 and OE2) that must both be low to enable the outputs. The 74HC573D has one output enable pin (OE) and one latch enable pin (LE). When LE is high, the latch is transparent and outputs follow inputs. When LE goes low, data is latched. When OE is high, outputs are in high-impedance state regardless of latch state.
Are the 74HC541D and 74HC573D available in the same package types?
Both devices are commonly available in SOIC-20, TSSOP-20, and other 20-pin packages. The "D" suffix typically denotes SOIC-20 in many manufacturer naming conventions, such as Nexperia and Texas Instruments. However, package availability may vary by manufacturer, so the specific datasheet should be consulted.
Which device is more suitable for bus driving applications?
The 74HC541D is specifically designed as a buffer/line driver for bus driving, with two output enable pins allowing flexible control of bus connection. The 74HC573D is also suitable for bus applications but adds latching capability, which can simplify bus timing by holding data stable. The choice depends on whether data storage is required in the application.