Part A
74VHC245FT
Toshiba Semiconductor et stockage
- Lifecycle
- Active
- Stock
- 4188 PCS
- Package
- TSSOP-20
- Series
- Logique - Buffers, lecteurs, récepteurs, émetteurs - récepteurs
Replacement verdict
Not a drop-in replacement
The 74VHC245FT and 74VHC02M are not functionally interchangeable. The 74VHC245FT is an octal bidirectional transceiver with 3-state outputs, while the 74VHC02M is a quad 2-input NOR gate. Their logic functions, channel configurations, pinouts, and output structures are fundamentally different, making direct substitution impossible without complete circuit redesign.
Different logic function
Different channel count
Different output type
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 | 74VHC245FT | 74VHC02M | Why it matters |
|---|---|---|---|
| Logic Function | Octal Bus Transceiver (3-state) | Quad 2-Input NOR Gate | Defines the core function; these devices are not functionally interchangeable as they perform entirely different logic operations. |
| Number of Channels / Gates | 8 channels (bidirectional) | 4 gates (2-input NOR) | Determines how many independent signal paths or logic operations the device can handle in a circuit. |
| Direction Control | Direction pin (A-to-B or B-to-A) | Not applicable (unidirectional logic) | Bus transceivers require direction control for bidirectional data flow, while logic gates do not have this feature. |
| Output Type | 3-state (tri-state) outputs | Standard push-pull CMOS output | Tri-state outputs allow bus sharing by high-impedance disconnection, which standard gate outputs cannot do. |
| Output Enable / Control | Output Enable (OE) and Direction (DIR) pins | None (always active) | Enable pins allow the device to be effectively removed from the bus, critical for shared data lines. |
| Supply Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | Both devices operate over the same VHC-family supply range, allowing use in 3.3 V and 5 V systems. |
| Logic Family | VHC (Very High Speed CMOS) | VHC (Very High Speed CMOS) | Same logic family ensures compatible input/output thresholds and similar propagation delays. |
| Propagation Delay (typical) | ~4.5 ns at 5 V | ~5.5 ns at 5 V | Affects maximum operating frequency and timing margins in synchronous designs. |
| Package | TSSOP-20 (thin shrink small outline) | SOIC-14 (small outline integrated circuit) | Different pin counts and footprints prevent direct PCB drop-in replacement without layout changes. |
| Pin Count | 20 pins | 14 pins | Pin count mismatch means the devices cannot share the same socket or footprint. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC245FT | 74VHC02M |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74VHC | 74VHC |
| Part Status | Active | Obsolete |
| Logic Type | Transceiver, 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 | 1 | - |
| Number of Bits per Element | 8 | - |
| Output Type | 3-State | - |
Frequently asked questions
What are the primary functions of the 74VHC245FT and 74VHC02M?
The 74VHC245FT is an octal bidirectional transceiver with 3-state outputs, designed for asynchronous two-way data bus communication. The 74VHC02M is a quad 2-input NOR gate, providing four independent logic gates for general-purpose logic inversion and combination.
Can the 74VHC245FT and 74VHC02M be used interchangeably in a design?
No. They are functionally different devices. The 74VHC245FT is a bus transceiver with direction and output-enable control, while the 74VHC02M is a logic gate array. Substitution requires a complete redesign of the surrounding circuit and cannot be done directly.
What are the package differences between the 74VHC245FT and 74VHC02M?
The 74VHC245FT is supplied in a TSSOP-20 package, while the 74VHC02M is supplied in an SOIC-14 package. The pin counts, body sizes, and PCB land patterns differ, so they are not footprint-compatible.
Do the 74VHC245FT and 74VHC02M operate from the same supply voltage range?
Yes. Both devices are members of the VHC family and are specified for a nominal supply voltage range of 2.0 V to 5.5 V, with characterized operation at 3.3 V and 5.0 V.
What are the output drive capabilities of the 74VHC245FT and 74VHC02M?
Both devices provide standard VHC-family output drive. The 74VHC245FT specifies ±8 mA output current at 5.0 V, and the 74VHC02M specifies ±8 mA output current at 5.0 V. These values are consistent with the 74VHC logic family specifications.
Are the 74VHC245FT and 74VHC02M available in automotive-qualified versions?
The 74VHC245FT and 74VHC02M are standard commercial-grade logic devices. Automotive-qualified equivalents, where available, are typically identified by a different part number suffix and should be confirmed against the manufacturer's official ordering information.
What are the typical propagation delays for the 74VHC245FT and 74VHC02M?
At 5.0 V supply, the 74VHC245FT has a typical propagation delay of approximately 3.8 ns for the A-to-B or B-to-A path. The 74VHC02M has a typical propagation delay of approximately 4.3 ns. Actual values depend on load capacitance and operating conditions.
Which device is better suited for bus interfacing in a microprocessor system?
The 74VHC245FT is the appropriate choice for bus interfacing because it provides eight bidirectional channels with 3-state outputs and direction control. The 74VHC02M is a logic gate and does not provide bus drive, isolation, or direction control functions.