Part A
74LVT245MTCX
Компания Fairchild Semiconductor
- Lifecycle
- Active
- Stock
- 3590 ПКС
- Package
- TSSOP-20
- Series
- Логика - буферы, драйверы, приемники, передатчики
Replacement verdict
Compatible functional replacement candidate
The 74LVT245MTCX and 74LVT2240MTC are both octal bus transceivers in the same TSSOP-20 package with identical 3.3V LVT logic family characteristics, making them viable functional replacement candidates. However, the 74LVT2240MTC features inverting outputs and integrated 30-ohm series termination resistors, while the 74LVT245MTCX provides non-inverting outputs without series damping resistors. Designers must account for the logic polarity inversion and the different output drive characteristics when substituting between these devices.
Output Polarity
Validation required
Output Drive Configuration
Validation required
Package Type
High match
Supply Voltage Range
High match
Parts at a glance
Part B
74LVT2240MTC
Онсеми
- Lifecycle
- Active
- Stock
- 5921 ПКС
- Package
- TSSOP-20
- Series
- Логика - буферы, драйверы, приемники, передатчики
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 74LVT245MTCX | 74LVT2240MTC | Why it matters |
|---|---|---|---|
| Logic Function | Octal Bus Transceiver (non-inverting, 3-state) | Octal Buffer/Line Driver (inverting, 3-state) | Determines the direction and polarity of signal flow; a transceiver supports bidirectional transfer while an inverting buffer reverses logic level, so they are not functionally interchangeable. |
| Number of Channels | 8 | 8 | Both handle 8-bit wide buses, so channel count alone does not differentiate them. |
| Direction Control | Direction pin (DIR) selects A-to-B or B-to-A | Two enable pins (1OE, 2OE) with fixed A-to-Y direction | The 245 supports bidirectional data flow, whereas the 2240 is unidirectional; this affects board routing and bus arbitration design. |
| Output Polarity | Non-inverting | Inverting | Inverting outputs change the logic sense of the signal, which is critical for correct data interpretation in a system. |
| Supply Voltage Range | 2.7 V to 3.6 V | 2.7 V to 3.6 V | Both operate in the LVT 3.3 V family range, so power supply compatibility is identical. |
| Output Drive Current | ±32 mA (at 3.0 V) | ±32 mA (at 3.0 V) | Matching drive strength means similar fan-out and trace-driving capability. |
| Propagation Delay | Approx. 2.5 ns (typical, 3.3 V) | Approx. 2.5 ns (typical, 3.3 V) | Similar timing performance supports comparable high-speed operation. |
| Package | TSSOP-20 | TSSOP-20 | Identical package and pin count allow the same PCB footprint, though pin functions differ. |
| Pin Configuration | DIR on pin 1, OE on pin 19 | 1OE on pin 1, 2OE on pin 19 | Different control pin assignments mean the devices are not drop-in replacements despite sharing the same package. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Both meet industrial temperature requirements, so environmental tolerance is equivalent. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74LVT245MTCX | 74LVT2240MTC |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74LVT | 74LVT |
| Part Status | Active | Obsolete |
| Logic Type | Transceiver, Non-Inverting | Buffer, Inverting |
| Number of Elements | 1 | 2 |
| Number of Bits per Element | 8 | 4 |
| Output Type | 3-State | 3-State |
| Current - Output High Low | 32mA, 64mA | 12mA, 12mA |
| Voltage - Supply | 2.7V ~ 3.6V | 2.7V ~ 3.6V |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the primary functional differences between the 74LVT245MTCX and the 74LVT2240MTC?
The 74LVT245MTCX is an octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous communication between data buses. The 74LVT2240MTC is an octal buffer/line driver with 3-state outputs, featuring a dual enable structure and series termination resistors on the outputs to reduce signal reflection. The 74LVT245MTCX provides direction control (DIR) and output enable (OE), while the 74LVT2240MTC provides two active-low output enables (1OE and 2OE) and no direction control.
Are the 74LVT245MTCX and 74LVT2240MTC pin-to-pin compatible?
No. The 74LVT245MTCX and 74LVT2240MTC have different pin functions and internal architectures. The 74LVT245MTCX uses a direction pin (DIR) and a single output enable (OE), whereas the 74LVT2240MTC uses two output enables (1OE, 2OE) and has no direction pin. Their pinouts are not interchangeable despite both being offered in TSSOP packages.
What is the difference in output drive and termination between these two devices?
The 74LVT245MTCX provides standard LVT output drive without integrated series termination resistors. The 74LVT2240MTC includes built-in series termination resistors on each output, which reduces overshoot and undershoot in high-speed signal lines. This makes the 74LVT2240MTC better suited for driving transmission lines with controlled impedance, while the 74LVT245MTCX is intended for general bus interfacing.
Can the 74LVT245MTCX be used as a drop-in replacement for the 74LVT2240MTC in an existing design?
No. Because the pin functions, control logic, and output termination differ, the 74LVT245MTCX cannot directly replace the 74LVT2240MTC without redesigning the PCB and validating the control signals. The 74LVT2240MTC requires two active-low enables and has series termination, while the 74LVT245MTCX requires a direction control and a single output enable.
What are the common applications for each device?
The 74LVT245MTCX is commonly used for bidirectional bus transceivers in backplane and memory interfaces where data flow direction must be switched. The 74LVT2240MTC is typically used as a buffer/line driver for clock distribution, address buses, and other unidirectional signal paths where series termination helps maintain signal integrity.
Do both devices operate at the same supply voltage and logic levels?
Yes. Both the 74LVT245MTCX and 74LVT2240MTC are LVT (Low-Voltage Technology) devices that operate from a 3.3 V nominal supply (typically 2.7 V to 3.6 V) and are 5 V tolerant on their inputs. They provide similar DC and AC characteristics for logic thresholds and propagation delays, but their output structures and control logic differ as noted.
What package options are available for the 74LVT245MTCX and 74LVT2240MTC?
Both devices are commonly offered in TSSOP (Thin Shrink Small Outline Package) and SOIC packages. The 74LVT245MTCX is typically supplied in a 20-pin TSSOP, while the 74LVT2240MTC is also available in a 20-pin TSSOP. Package dimensions and pin counts are the same, but pin assignments differ, so they are not interchangeable without layout changes.
Which device is better for reducing signal reflections on a bus?
The 74LVT2240MTC is better for reducing signal reflections because it integrates series termination resistors on each output. The 74LVT245MTCX does not include these resistors, so external termination may be required to achieve similar signal integrity performance in high-speed bus applications.