Part A
74VHC244FT
Toshiba Semiconductor et stockage
- Lifecycle
- Active
- Stock
- 2156 PCS
- Package
- TSSOP-20
- Series
- Logique - Buffers, lecteurs, récepteurs, émetteurs - récepteurs
Replacement verdict
Not a drop-in replacement
The 74VHC244FT and 74VHC02M are not functionally interchangeable. The 74VHC244FT is an octal non-inverting buffer/line driver with 3-state outputs, while the 74VHC02M is a quad 2-input NOR gate. They differ in logic function, output type, channel count, and pinout, so direct substitution is not possible without circuit redesign.
Different logic function
Different output type
Different channel count
Different pinout
Parts at a glance
Part B
74VHC02M
Semi - conducteurs
- Lifecycle
- Active
- Stock
- 5373 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 | 74VHC244FT | 74VHC02M | Why it matters |
|---|---|---|---|
| Logic Function | Octal Buffer/Line Driver with 3-State Outputs | Quad 2-Input NOR Gate | Defines the fundamental logic operation; these devices perform completely different functions and are not functionally interchangeable. |
| Number of Channels / Gates | 8 buffers | 4 gates | Determines how many independent signal paths can be processed, affecting circuit density and design flexibility. |
| Output Type | 3-State | Push-Pull (totem-pole) | 3-state outputs allow bus sharing and high-impedance isolation, while push-pull outputs cannot be tied together on a shared bus. |
| Inputs per Channel | 1 | 2 | Buffer channels accept a single input, whereas NOR gates require two inputs to produce the logic function. |
| Control Inputs | Two active-low output enable (OE) pins | None | Enable pins allow the buffer outputs to be placed in high-impedance state for bus arbitration; NOR gates have no such control. |
| Supply Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | Both parts share the VHC family supply range, so they are compatible with the same logic-level power rails. |
| Logic Family | 74VHC | 74VHC | Same family ensures comparable switching thresholds, drive strength, and noise margins when used together. |
| Propagation Delay (typical) | ~3.8 ns at 5 V | ~4.3 ns at 5 V | Affects maximum operating frequency and timing margins in synchronous or delay-sensitive designs. |
| Output Drive Current | ±8 mA | ±8 mA | Determines fan-out capability and ability to drive loads such as LEDs or transmission lines. |
| Package | TSSOP-20 | SOIC-14 | Different pin counts and footprints prevent direct drop-in replacement on the same PCB pad layout. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC244FT | 74VHC02M |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74VHC | 74VHC |
| Part Status | Active | Obsolete |
| Logic Type | Buffer, Non-Inverting | NOR Gate |
| Number of Circuits | - | 4 |
| Number of Inputs | - | 2 |
| Voltage - Supply | 2V ~ 5.5V | 2V ~ 5.5V |
| Current - Quiescent (Max) | - | 2 µA |
| Current - Output High Low | 8mA, 8mA | 8mA, 8mA |
| Logic Level - Low | - | 0.5V |
| Logic Level - High | - | 1.5V |
| Max Propagation Delay @ V Max CL | - | 7.5ns @ 5V, 50pF |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Number of Elements | 2 | - |
| Number of Bits per Element | 4 | - |
| Output Type | 3-State | - |
Frequently asked questions
What are the primary functional differences between the 74VHC244FT and the 74VHC02M?
The 74VHC244FT is an octal non-inverting buffer/line driver with 3-state outputs, while the 74VHC02M is a quad 2-input NOR gate. The 74VHC244FT is designed for signal buffering and bus driving, whereas the 74VHC02M performs logic NOR operations.
Are the 74VHC244FT and 74VHC02M pin-compatible?
No. The 74VHC244FT is typically supplied in a 20-pin package (e.g., TSSOP20), and the 74VHC02M is supplied in a 14-pin package (e.g., SOIC14). They have different pin counts and pin functions, so they are not pin-compatible.
Can the 74VHC244FT and 74VHC02M operate from the same supply voltage?
Yes. Both devices are members of the 74VHC family and are specified for a nominal supply voltage range of 2.0 V to 5.5 V, with typical operation at 3.3 V or 5 V.
What is the logic function of the 74VHC02M?
The 74VHC02M contains four independent 2-input NOR gates. Each gate outputs a HIGH logic level only when both inputs are LOW; otherwise, the output is LOW.
Does the 74VHC244FT have 3-state outputs?
Yes. The 74VHC244FT features 3-state outputs controlled by two active-low output enable pins (1OE and 2OE). When disabled, the outputs enter a high-impedance state, allowing direct connection to a shared bus.
Are the 74VHC244FT and 74VHC02M interchangeable in a design?
No. Because they implement different logic functions, have different pin counts, and different package footprints, they cannot be used as direct substitutes for one another without redesigning the circuit.
What are the typical propagation delays for these devices?
At a 5 V supply, the 74VHC244FT typically exhibits a propagation delay (tPD) of approximately 3.8 ns, while the 74VHC02M typically exhibits a tPD of approximately 4.3 ns. Actual values depend on load conditions and are specified in the respective manufacturer datasheets.