Part A
74VHC14MTCX
Semi - conducteurs
- Lifecycle
- Active
- Stock
- 4330 PCS
- Package
- TSSOP-14
- Series
- Logique - portes et Onduleurs
Replacement verdict
Not a drop-in replacement
The 74VHC14MTCX and 74VHCT05ATTR are not functionally interchangeable. The 74VHC14MTCX is a hex Schmitt-trigger inverter with push-pull CMOS outputs, while the 74VHCT05ATTR is a hex inverter with open-drain outputs. This fundamental output architecture difference, combined with differing logic thresholds, package footprints, and pull-up requirements, prevents direct substitution without circuit redesign.
Different output type
Different logic thresholds
Different package footprint
External pull-up may be required
Parts at a glance
Part B
74VHCT05ATTR
Semi - conducteurs optiques
- Lifecycle
- Active
- Stock
- 3384 PCS
- Series
- Logique - portes et Onduleurs
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74VHC14MTCX | 74VHCT05ATTR | Why it matters |
|---|---|---|---|
| Logic Function | Hex Schmitt Trigger Inverter | Hex Inverter with Open-Drain Outputs | The logic function determines the basic signal-processing behavior; a Schmitt trigger inverter and an open-drain inverter are not functionally interchangeable in most circuits. |
| Output Type | Push-Pull (CMOS) | Open-Drain | Push-pull outputs actively drive both high and low, while open-drain outputs require an external pull-up resistor and cannot source current, affecting direct substitutability. |
| Input Type | Schmitt Trigger | Standard CMOS/TTL-compatible | Schmitt trigger inputs provide hysteresis for noise immunity on slow or noisy signals; standard inputs lack this hysteresis, changing noise margin behavior. |
| Supply Voltage Range | 2.0 V to 5.5 V | 4.5 V to 5.5 V | The VHC device operates over a wider low-voltage range, while the VHCT device is restricted to 5 V systems, limiting where each can be used. |
| Logic Family | VHC (Very High Speed CMOS) | VHCT (Very High Speed CMOS with TTL-compatible inputs) | VHC and VHCT families differ in input threshold compatibility; VHCT inputs are TTL-compatible at 5 V, while VHC inputs are CMOS-level referenced. |
| Propagation Delay (typical) | ~5.5 ns at 5 V | ~6.5 ns at 5 V | Propagation delay affects timing margins in synchronous and high-speed signal paths; a slower device may not meet timing requirements. |
| Output Drive Current | ±8 mA | Sink only (open-drain), typically 8 mA | Drive current capability determines fan-out and the ability to drive loads; open-drain outputs cannot source current, requiring different external circuitry. |
| Package | TSSOP-14 | TSSOP-14 | Package compatibility ensures the part can be placed on the same PCB footprint; identical packages simplify physical substitution. |
| Number of Circuits | 6 | 6 | Matching circuit count ensures the same number of signal channels are available, which is essential for pin-compatible replacement. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | The operating temperature range must cover the application environment; identical ranges mean neither device is disadvantaged thermally. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC14MTCX | 74VHCT05ATTR |
|---|---|---|
| Supplier | - | STMicroelectronics |
| Series | - | 74VHCT |
| Part Status | Active | Obsolete |
| Logic Type | - | Inverter |
| Number of Circuits | - | 6 |
| Number of Inputs | - | 1 |
| Features | - | Open Drain |
| Voltage - Supply | - | 4.5V ~ 5.5V |
| Current - Quiescent (Max) | - | 2 µA |
| Current - Output High Low | - | -, 8mA |
| Logic Level - Low | - | 0.8V |
| Logic Level - High | - | 2V |
| Max Propagation Delay @ V Max CL | - | 9.8ns @ 5V, 50pF |
| Operating Temperature | - | -55°C ~ 125°C |
| Mounting Type | - | Surface Mount |
Frequently asked questions
What are the main functional differences between the 74VHC14MTCX and the 74VHCT05ATTR?
The 74VHC14MTCX is a hex Schmitt-trigger inverter, while the 74VHCT05ATTR is a hex inverter with open-drain outputs. The 74VHC14MTCX provides buffered complementary outputs with Schmitt-trigger input hysteresis, whereas the 74VHCT05ATTR provides open-drain outputs that require external pull-up resistors and does not include Schmitt-trigger inputs.
Are the 74VHC14MTCX and 74VHCT05ATTR pin-to-pin compatible?
No. The 74VHC14MTCX is supplied in a TSSOP-14 package, and the 74VHCT05ATTR is supplied in a TSSOP-14 package as well, but the output structures differ. The 74VHC14MTCX has push-pull outputs, while the 74VHCT05ATTR has open-drain outputs. Pin functions are not equivalent, so they are not direct substitutes without circuit redesign.
Can the 74VHC14MTCX drive a load that requires an open-drain output?
No. The 74VHC14MTCX has a push-pull output stage and cannot be used as an open-drain output without additional circuitry. The 74VHCT05ATTR is specifically designed with open-drain outputs for wired-OR or level-shifting applications.
What are the typical operating voltage ranges for these devices?
The 74VHC14MTCX operates over a recommended supply voltage range of 2.0 V to 5.5 V. The 74VHCT05ATTR operates over a recommended supply voltage range of 4.5 V to 5.5 V. The 74VHCT05ATTR is not specified for operation below 4.5 V.
Do both devices have Schmitt-trigger inputs?
No. The 74VHC14MTCX has Schmitt-trigger inputs with hysteresis, making it suitable for slow or noisy input signals. The 74VHCT05ATTR does not have Schmitt-trigger inputs; it has standard CMOS input thresholds.
Which device is better for interfacing with a 3.3 V logic system when powered from 5 V?
The 74VHCT05ATTR is not recommended for 3.3 V to 5 V translation because its inputs are not 3.3 V tolerant when powered at 5 V. The 74VHC14MTCX is also not specified for 3.3 V input when powered at 5 V. Neither device should be used for direct 3.3 V to 5 V level shifting without external components or a dedicated level translator.
What is the output drive capability of each device?
The 74VHC14MTCX provides standard push-pull outputs with symmetric drive capability, typically ±8 mA at 5 V. The 74VHCT05ATTR provides open-drain outputs with a sink current capability typically of 8 mA; the high level is determined by an external pull-up resistor and the connected supply.
Are these devices available in the same package type?
Yes, both the 74VHC14MTCX and the 74VHCT05ATTR are offered in TSSOP-14 packages. However, package similarity does not imply functional equivalence; the output configuration and input thresholds differ significantly.
Can the 74VHCT05ATTR be used as a direct replacement for the 74VHC14MTCX in an existing design?
No. The 74VHCT05ATTR has open-drain outputs and no Schmitt-trigger inputs, while the 74VHC14MTCX has push-pull outputs and Schmitt-trigger inputs. A direct replacement would require circuit modifications, including adding pull-up resistors and verifying input signal compatibility.