Part A
74LCX244MTC
Semi - conducteurs
- Lifecycle
- Active
- Stock
- 5042 PCS
- Series
- Logique - Buffers, lecteurs, récepteurs, émetteurs - récepteurs
Replacement verdict
Not a drop-in replacement
The 74LCX244MTC and 74LCX14TTR are not functionally interchangeable. The 74LCX244MTC is a non-inverting octal buffer/line driver with 3-state outputs, while the 74LCX14TTR is a hex inverting Schmitt trigger. They differ in logic function, channel count, output type, and input threshold characteristics, making direct substitution impossible without circuit redesign.
Different logic function
Different channel count
Different output type
Different input threshold
Parts at a glance
Part B
74LCX14TTR
Semi - conducteurs optiques
- Lifecycle
- Active
- Stock
- 5109 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 | 74LCX244MTC | 74LCX14TTR | Why it matters |
|---|---|---|---|
| Logic Function | Octal Buffer/Line Driver with 3-State Outputs | Hex Inverter with Schmitt Trigger Inputs | These are fundamentally different logic functions, so they are not functionally interchangeable in a circuit. |
| Number of Channels | 8 | 6 | Channel count determines how many independent signal lines the device can process. |
| Output Type | 3-State | Push-Pull | 3-state outputs allow bus sharing, while push-pull outputs cannot be tied together on a shared bus. |
| Input Type | Standard CMOS | Schmitt Trigger | Schmitt trigger inputs provide hysteresis for noise immunity and slow signal edges, which standard inputs do not. |
| Direction | Unidirectional (with dual enable) | Unidirectional (inverting) | The 244 buffers signals non-inverting, while the 14 inverts the signal, affecting logic polarity. |
| Supply Voltage Range | 2.0 V to 3.6 V | 2.0 V to 3.6 V | Both operate over the same low-voltage range, supporting 3.3 V and lower logic systems. |
| Propagation Delay (typ) | 6.5 ns at 3.3 V | 6.5 ns at 3.3 V | Similar propagation delay means comparable timing performance in signal paths. |
| Package | TSSOP-20 | TSSOP-14 | Different pin counts and footprints prevent direct drop-in replacement on the same PCB pad layout. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings suit both parts to the same industrial environments. |
| Output Drive Current | ±24 mA | ±24 mA | Matching drive strength means similar fan-out and load-driving capability. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74LCX244MTC | 74LCX14TTR |
|---|---|---|
| Supplier | - | STMicroelectronics |
| Series | 74LCX | 74LCX |
| Part Status | Active | Obsolete |
| Logic Type | Buffer, Non-Inverting | Inverter |
| Number of Circuits | - | 6 |
| Number of Inputs | - | 1 |
| Features | - | Schmitt Trigger |
| Voltage - Supply | 2V ~ 3.6V | 2V ~ 3.6V |
| Current - Quiescent (Max) | - | 10 µA |
| Current - Output High Low | - | 24mA, 24mA |
| Logic Level - Low | - | 0.6V |
| Logic Level - High | - | 2.2V |
| Max Propagation Delay @ V Max CL | - | 5ns @ 3.3V, 50pF |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Base Product Number | 74LCX244 | - |
| Number of Elements | 2 | - |
| Number of Bits per Element | 4 | - |
| Output Type | 3-State | - |
| Current - Output High, Low | 24mA, 24mA | - |
| Packaging | Tube | - |
Frequently asked questions
What are the primary functional differences between the 74LCX244MTC and the 74LCX14TTR?
The 74LCX244MTC is an octal non-inverting buffer/line driver with 3-state outputs, while the 74LCX14TTR is a hex inverting Schmitt trigger. The 74LCX244MTC is designed for bus driving and signal buffering, whereas the 74LCX14TTR is intended for signal conditioning and waveform shaping of slow or noisy input signals.
Are the 74LCX244MTC and 74LCX14TTR pin-compatible?
No. The 74LCX244MTC is supplied in a 20-pin TSSOP package, and the 74LCX14TTR is supplied in a 14-pin TSSOP package. They have different pin counts and pinouts, so they are not pin-compatible or directly interchangeable on the same PCB footprint.
Can the 74LCX244MTC and 74LCX14TTR operate from the same supply voltage?
Yes. Both devices are part of the LCX family and are specified for a nominal 3.3 V supply, with a recommended operating supply voltage range of 2.0 V to 3.6 V. This makes them suitable for mixed 3.3 V logic designs.
Does the 74LCX244MTC have 3-state outputs while the 74LCX14TTR does not?
Yes. The 74LCX244MTC features 3-state outputs controlled by two active-low output enable pins, allowing the outputs to be placed in a high-impedance state for bus sharing. The 74LCX14TTR has standard push-pull outputs and does not provide a high-impedance output state.
Which device is better suited for cleaning up noisy or slow input signals?
The 74LCX14TTR is better suited for this purpose because it is a Schmitt trigger device with defined positive and negative input threshold voltages, providing hysteresis that improves noise immunity and sharpens slow input edges. The 74LCX244MTC is a standard buffer and does not include Schmitt trigger input hysteresis.
What are the output drive capabilities of the 74LCX244MTC and 74LCX14TTR?
Both devices are specified with a balanced output drive of ±24 mA at 3.0 V, which is typical for LCX-family logic. This allows them to drive moderate capacitive loads and resistive terminations in 3.3 V systems.
Are the 74LCX244MTC and 74LCX14TTR available in the same package type?
No. The 74LCX244MTC is offered in a 20-pin TSSOP package, while the 74LCX14TTR is offered in a 14-pin TSSOP package. The package type family is similar, but the pin counts and body sizes differ.
Can the 74LCX244MTC and 74LCX14TTR be used in the same 3.3 V logic design?
Yes, both devices are compatible with 3.3 V logic levels and can be used in the same system, provided that the designer accounts for their different functions, pinouts, and package sizes. The 74LCX244MTC would typically be used for bus buffering, while the 74LCX14TTR would be used for input signal conditioning.