Part A
74VHC14MX
Fairchild Halbleiter
- Lifecycle
- Active
- Stock
- 3753 Stückzahl
- Package
- SOIC-14
- Series
- Logic-Gates und Wechselrichter
Replacement verdict
Not a drop-in replacement
The 74VHC14MX and 74VHC08MTR are not functionally interchangeable despite sharing the same VHC logic family and SOIC-14 footprint. The 74VHC14MX provides six inverting Schmitt-trigger buffers with hysteresis, while the 74VHC08MTR provides four 2-input AND gates with standard CMOS input thresholds. The differing logic function, gate count, and input threshold behavior make direct substitution impossible without circuit redesign.
Different logic function
Different gate count
Different input threshold
Different output drive
Parts at a glance
Part B
74VHC08MTR
STMikroelektronik
- Lifecycle
- Active
- Stock
- 2495 Stückzahl
- Series
- Logic-Gates und Wechselrichter
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74VHC14MX | 74VHC08MTR | Why it matters |
|---|---|---|---|
| Logic Function | Hex Inverter with Schmitt Trigger Inputs | Quad 2-Input AND Gate | Defines the fundamental logic operation; these devices are not functionally interchangeable. |
| Number of Circuits | 6 | 4 | Determines how many independent logic elements are available in a single package. |
| Number of Inputs per Circuit | 1 | 2 | Affects the logic equation each element can implement and overall circuit design. |
| Schmitt Trigger Input | Yes | No | Schmitt trigger inputs provide hysteresis for noise immunity and slow input signals. |
| Output Type | Inverting | Non-Inverting | Determines the polarity of the output relative to the input logic level. |
| Supply Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | Defines the compatible power supply window for the device. |
| Logic Family | VHC | VHC | Indicates compatible logic levels and switching characteristics within a family. |
| Mounting Type | Surface Mount | Surface Mount | Determines the assembly method and PCB footprint compatibility. |
| Package / Case | 14-SOIC | 14-SOIC | Physical package must match the PCB land pattern for direct replacement. |
| Operating Temperature Range | -40°C to 85°C | -40°C to 85°C | Ensures reliable operation across the intended environmental conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC14MX | 74VHC08MTR |
|---|---|---|
| Supplier | - | STMicroelectronics |
| Series | 74VHC | 74VHC |
| Part Status | Active | Obsolete |
| Logic Type | Inverter | AND Gate |
| Number of Circuits | 6 | 4 |
| Number of Inputs | 1 | 2 |
| Voltage - Supply | 2V ~ 5.5V | 2V ~ 5.5V |
| Current - Quiescent (Max) | 2 µA | 2 µA |
| Current - Output High Low | 8mA, 8mA | 8mA, 8mA |
| Logic Level - Low | 0.9V ~ 1.65V | 0.5V |
| Logic Level - High | 2.2V ~ 3.85V | 1.5V |
| Max Propagation Delay @ V Max CL | 10.6ns @ 5V, 50pF | 7.9ns @ 5V, 50pF |
| Operating Temperature | -40°C ~ 85°C | -55°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Features | Schmitt Trigger | - |
Frequently asked questions
What are the primary functional differences between the 74VHC14MX and the 74VHC08MTR?
The 74VHC14MX is a hex Schmitt-trigger inverter, meaning it provides six independent inverter gates with hysteresis on the inputs. The 74VHC08MTR is a quad 2-input AND gate, providing four independent AND gates. They perform fundamentally different logic functions and are not functionally equivalent.
Are the 74VHC14MX and 74VHC08MTR pin-to-pin compatible?
No. Both devices are offered in similar 14-pin SOIC packages, but their internal gate configurations and pin assignments differ. The 74VHC14MX uses all 14 pins for six inverters (power, ground, and 12 signal pins), while the 74VHC08MTR uses 14 pins for four 2-input AND gates (power, ground, and 12 signal pins). The signal pin functions are not interchangeable.
Can the 74VHC14MX be used as a direct substitute for the 74VHC08MTR in an existing design?
No. The 74VHC14MX is an inverting Schmitt-trigger device, while the 74VHC08MTR is a non-inverting AND gate. Substituting one for the other would invert logic states and change the circuit's logical behavior. A direct substitution is not possible without redesigning the surrounding circuitry.
Do both devices operate at the same supply voltage range?
Yes. Both the 74VHC14MX and 74VHC08MTR are VHC-family CMOS logic devices specified for a supply voltage range of 2.0 V to 5.5 V, per their respective manufacturer datasheets.
What is the significance of the Schmitt-trigger input on the 74VHC14MX compared to the 74VHC08MTR?
The 74VHC14MX features Schmitt-trigger inputs with defined positive and negative threshold voltages (hysteresis), making it suitable for slow or noisy input signals. The 74VHC08MTR has standard CMOS inputs without Schmitt-trigger hysteresis, so it is intended for clean, fast-edged logic signals.
Are both devices available in the same package type?
Both the 74VHC14MX and 74VHC08MTR are commonly available in 14-pin SOIC packages. However, package availability may vary by manufacturer and ordering suffix, so the specific datasheet for each ordered part number should be consulted.
Which device is better suited for signal conditioning of noisy inputs?
The 74VHC14MX is better suited for signal conditioning of noisy or slow-rising inputs because its Schmitt-trigger inputs provide hysteresis, improving noise immunity. The 74VHC08MTR does not have Schmitt-trigger inputs and is not intended for that purpose.
Do both devices have the same output drive capability?
Both are VHC-family CMOS logic devices and typically provide symmetrical output drive in the range of ±8 mA at 5 V VCC, as specified in their respective datasheets. However, exact drive current specifications should be verified from the manufacturer datasheet for the specific part number and test conditions.