Part A
74HC540D
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 5312 PCS
- Package
- SOIC-20
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Compatible functional replacement candidate
The 74HC540D and 74HC541D,653 are functionally related octal buffer/driver ICs from the same 74HC logic family, but they are not pin-compatible drop-in replacements due to their inverted versus non-inverted output configurations. The 74HC540D provides inverting outputs with active-low output enable pins, while the 74HC541D,653 provides non-inverting outputs with active-low output enable pins. Designers must account for the logic polarity difference when substituting between these devices.
Output Type
High match
Package Type
High match
Logic Family
High match
Logic Polarity
Validation required
Parts at a glance
Part B
74HC541D,653
NXP USA Inc.
- Lifecycle
- Active
- Stock
- 6304 PCS
- Package
- SOIC-20
- Series
- Logic - 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 | 74HC540D | 74HC541D,653 | Why it matters |
|---|---|---|---|
| Logic Function | Octal buffer/line driver with 3-state outputs, inverting | Octal buffer/line driver with 3-state outputs, non-inverting | The inversion polarity determines signal phase; substituting one for the other flips logic levels and can break circuit functionality. |
| Number of Channels | 8 | 8 | Channel count must match to drive the same number of signal lines in a bus or interface. |
| Output Type | 3-state | 3-state | 3-state outputs allow bus sharing by entering high-impedance mode, essential for multiplexed bus architectures. |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | The operating voltage window must cover the system rail to ensure reliable logic thresholds and output levels. |
| Output Drive Current | ±6 mA | ±6 mA | Drive current determines fan-out and the ability to drive capacitive or resistive loads without degrading logic levels. |
| Propagation Delay | ~8 ns at 5 V | ~8 ns at 5 V | Propagation delay affects timing margins in synchronous systems and maximum operating frequency. |
| Package | SO-20 | SO-20 | Package footprint and pinout must match for drop-in board-level replacement. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Temperature range must cover the application environment to guarantee specified electrical performance. |
| Pin Count | 20 | 20 | Pin count and pinout compatibility are required for physical and electrical interchangeability. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74HC540D | 74HC541D,653 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | 74HC | 74HC |
| Part Status | Active | Active |
| Logic Type | Buffer, Inverting | Buffer, Non-Inverting |
| Number of Elements | 1 | 1 |
| Number of Bits per Element | 8 | 8 |
| Output Type | 3-State | 3-State |
| Current - Output High Low | 7.8mA, 7.8mA | 7.8mA, 7.8mA |
| Voltage - Supply | 2V ~ 6V | 2V ~ 6V |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What is the main functional difference between the 74HC540D and the 74HC541D,653?
The 74HC540D is an octal buffer/line driver with inverting 3-state outputs, while the 74HC541D,653 is an octal buffer/line driver with non-inverting 3-state outputs. Both have the same pinout and drive capability, but the 74HC540D inverts the input signal at the output, whereas the 74HC541D,653 does not.
Are the 74HC540D and 74HC541D,653 pin-compatible?
Yes, both devices are offered in the same SO-16 package and share an identical pinout. This allows them to be used interchangeably on the same PCB footprint, provided the logic inversion difference is accounted for in the design.
What are the output drive capabilities of these devices?
Both the 74HC540D and 74HC541D,653 provide standard HC-family output drive, typically capable of sourcing or sinking up to 6 mA per output at 5 V VCC, with a maximum output current of 35 mA per pin and 70 mA per package under absolute maximum ratings. These values are consistent across both parts.
What is the difference in propagation delay between the 74HC540D and 74HC541D,653?
Both devices have essentially identical propagation delay characteristics, as they are based on the same HC CMOS process. At 5 V VCC and 25 °C, the typical propagation delay is approximately 12 ns to 15 ns for both the inverting and non-inverting versions, with the non-inverting 74HC541D,653 often showing a slightly shorter delay due to the absence of an inversion stage.
Can the 74HC540D be replaced by the 74HC541D,653 without any design changes?
No, a direct replacement without design changes is not possible because the 74HC540D inverts the signal while the 74HC541D,653 does not. The system logic must be reviewed to ensure that the polarity change does not cause malfunction. If the inversion is compensated elsewhere in the signal chain, the replacement may be acceptable.
What are the operating voltage and temperature ranges for these devices?
Both the 74HC540D and 74HC541D,653 operate over a supply voltage range of 2 V to 6 V and a temperature range of -40 °C to +125 °C, making them suitable for a wide range of industrial and consumer applications.
Do these devices have 3-state outputs, and how are they controlled?
Yes, both the 74HC540D and 74HC541D,653 feature 3-state outputs. Each device has two active-low output enable pins (OE1 and OE2). When either enable pin is high, the corresponding outputs are placed in a high-impedance state, allowing the device to be used in bus-oriented systems.
What is the difference in input capacitance between the 74HC540D and 74HC541D,653?
Both devices have similar input capacitance, typically around 3.5 pF at 25 °C, as they use the same HC CMOS input structure. Any minor differences are within the specified tolerance and do not affect interchangeability in terms of input loading.