Part A
74LCX125MTCX
onsemi
- Lifecycle
- Active
- Stock
- 6950 PCS
- Package
- TSSOP-14
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Not a drop-in replacement
The 74LCX125MTCX and 74LCX00MTC are not functionally interchangeable despite sharing the same LCX logic family and TSSOP-14 package. The 74LCX125MTCX is a quad bus buffer with 3-state outputs, while the 74LCX00MTC is a quad 2-input NAND gate with standard push-pull outputs. Their differing logic functions, output structures, and pin assignments make direct substitution impossible without circuit redesign.
Different logic function
Different output type
Different pinout
Different input configuration
Parts at a glance
Part B
74LCX00MTC
onsemi
- Lifecycle
- Active
- Stock
- 8585 PCS
- Series
- Logic - Gates and Inverters
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74LCX125MTCX | 74LCX00MTC | Why it matters |
|---|---|---|---|
| Logic Function | Quad Buffer/Line Driver with 3-State Outputs | Quad 2-Input NAND Gate | Defines the fundamental logic operation; these devices are not functionally interchangeable. |
| Number of Gates/Buffers | 4 | 4 | Indicates how many independent channels are available in the package. |
| Number of Inputs per Channel | 1 | 2 | Determines the logic capability; a buffer has one input while a NAND gate requires two. |
| Output Type | 3-State | Push-Pull | 3-state outputs allow bus sharing, while push-pull outputs cannot be tied together. |
| Control Input | Output Enable (active LOW) | None | The enable pin on the buffer allows high-impedance state control, which the NAND gate lacks. |
| Propagation Delay (tpd) | 6.5 ns max at 3.3V | 5.5 ns max at 3.3V | Affects maximum operating frequency and timing margins in synchronous designs. |
| Supply Voltage Range | 2.0V to 3.6V | 2.0V to 3.6V | Both support low-voltage operation, but must match system supply rails. |
| Output Drive Current (IOL/IOH) | 24 mA / -24 mA | 24 mA / -24 mA | Determines fan-out and ability to drive heavy loads or long traces. |
| Package Type | TSSOP-14 | TSSOP-14 | Physical footprint and pin count must match for PCB compatibility. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Ensures reliable operation across industrial temperature environments. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74LCX125MTCX | 74LCX00MTC |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74LCX | 74LCX |
| Part Status | Active | Obsolete |
| Logic Type | Buffer, Non-Inverting | NAND Gate |
| Number of Circuits | - | 4 |
| Number of Inputs | - | 2 |
| Voltage - Supply | 2V ~ 3.6V | 2V ~ 3.6V |
| Current - Quiescent (Max) | - | 10 µA |
| Current - Output High Low | 24mA, 24mA | 24mA, 24mA |
| Logic Level - Low | - | 0.7V ~ 0.8V |
| Logic Level - High | - | 1.7V ~ 2V |
| Max Propagation Delay @ V Max CL | - | 5.2ns @ 3.3V, 50pF |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Number of Elements | 4 | - |
| Number of Bits per Element | 1 | - |
| Output Type | 3-State | - |
Frequently asked questions
What are the primary functional differences between the 74LCX125MTCX and the 74LCX00MTC?
The 74LCX125MTCX is a quad buffer/line driver with 3-state outputs, while the 74LCX00MTC is a quad 2-input NAND gate. The 74LCX125MTCX is used for signal buffering and bus driving with high-impedance output capability, whereas the 74LCX00MTC performs logic NAND operations without 3-state outputs.
Are the 74LCX125MTCX and 74LCX00MTC pin-to-pin compatible?
No. Both devices are offered in the same 14-pin TSSOP package (MTC suffix), but their pin functions differ. The 74LCX125MTCX has output enable pins and 3-state outputs, while the 74LCX00MTC has standard NAND gate inputs and outputs. They cannot be used interchangeably without circuit redesign.
What is the operating voltage range for both the 74LCX125MTCX and 74LCX00MTC?
Both devices operate over a supply voltage range of 2.0 V to 3.6 V, typical of the LCX family. They are designed for low-voltage applications and are not recommended for 5 V supply operation, though inputs may be 5 V tolerant depending on the specific manufacturer datasheet.
Can the 74LCX125MTCX and 74LCX00MTC drive the same load currents?
Both devices typically provide ±24 mA output drive at 3.0 V VCC, as specified in LCX family datasheets. However, the 74LCX125MTCX includes 3-state outputs, which affects how the output can be connected in bus-oriented systems, while the 74LCX00MTC provides standard push-pull outputs.
What are the package and pin count specifications for the 74LCX125MTCX and 74LCX00MTC?
Both the 74LCX125MTCX and 74LCX00MTC are offered in a 14-pin TSSOP package, indicated by the MTC suffix. The TSSOP package is suitable for surface-mount assembly and offers a compact footprint for space-constrained designs.
Do both devices support 5 V tolerant inputs?
Yes, LCX-family devices including the 74LCX125MTCX and 74LCX00MTC typically feature 5 V tolerant inputs when operated at VCC between 2.0 V and 3.6 V. This allows interfacing with 5 V logic systems without additional level shifting, but always verify the specific manufacturer datasheet for exact ratings.
Which device is better suited for bus driving applications?
The 74LCX125MTCX is better suited for bus driving because it features 3-state outputs that can be placed in high-impedance mode, allowing multiple devices to share a common bus. The 74LCX00MTC lacks 3-state outputs and is intended for general-purpose logic gating.
What are the propagation delay characteristics of the 74LCX125MTCX and 74LCX00MTC?
Both devices typically exhibit propagation delays in the range of approximately 3.0 ns to 6.5 ns at 3.3 V VCC, depending on load conditions and manufacturer. The 74LCX00MTC NAND gate and 74LCX125MTCX buffer have similar speed grades within the LCX family, but exact values should be confirmed from the respective datasheets.