Part A
74VHC245FT
Toshiba Semiconductor và lưu trữ
- Lifecycle
- Active
- Stock
- 4188 PCS
- Package
- TSSOP-20
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Not a drop-in replacement
The 74VHC245FT and 74VHC164MTCX are not functionally interchangeable. The 74VHC245FT is an octal bidirectional transceiver with 3-state outputs, while the 74VHC164MTCX is an 8-bit serial-in/parallel-out shift register. Their logic functions, pin configurations, and control interfaces differ fundamentally, so neither device can directly substitute for the other in an existing design.
Different logic function
Different pinout
Different control interface
Different data flow direction
Parts at a glance
Part B
74VHC164MTCX
onsemi
- Lifecycle
- Active
- Stock
- 2495 PCS
- Package
- TSSOP-14
- Series
- Logic - Shift Registers
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 | 74VHC164MTCX | Why it matters |
|---|---|---|---|
| Logic Function | Octal Bus Transceiver, 3-State | 8-Bit Serial-In/Parallel-Out Shift Register | The core logic function determines whether the devices are functionally interchangeable; these two parts perform entirely different operations. |
| Number of Pins | 20 | 14 | Pin count affects PCB footprint and package compatibility, so a different count prevents direct drop-in replacement. |
| Package Type | TSSOP-20 | TSSOP-14 | Package type and body size must match the board layout for physical substitutability. |
| Direction of Data Flow | Bidirectional (A to B or B to A) | Unidirectional (serial in, parallel out) | Data flow direction defines the device's role in a circuit and cannot be substituted between these two functions. |
| Output Type | 3-State | Push-Pull | Output configuration affects bus sharing and drive capability, which are critical for system-level compatibility. |
| Number of Outputs | 8 | 8 | Although both have 8 outputs, the output behavior and control differ, so this alone does not ensure substitutability. |
| Control Inputs | Output Enable (OE), Direction (DIR) | Clock (CP), Clear (CLR) | Control signals determine how the device is operated and must match the intended circuit logic. |
| Supply Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | Both support the same VHC voltage range, so power supply compatibility is not a differentiator. |
| Propagation Delay (typical) | ~4.5 ns at 5 V | ~6.0 ns at 5 V | Timing differences can affect signal integrity and maximum operating frequency in synchronous designs. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Matching temperature ranges ensures both parts can be used in the same environmental conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC245FT | 74VHC164MTCX |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74VHC | 74VHC |
| Part Status | Active | Active |
| Logic Type | Transceiver, Non-Inverting | Shift Register |
| Output Type | 3-State | Push-Pull |
| Number of Elements | 1 | 1 |
| Number of Bits per Element | 8 | 8 |
| Function | - | Serial to Parallel |
| Voltage - Supply | 2V ~ 5.5V | 2V ~ 5.5V |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Current - Output High Low | 8mA, 8mA | - |
Frequently asked questions
What are the primary functional differences between the 74VHC245FT and the 74VHC164MTCX?
The 74VHC245FT is an octal bidirectional transceiver with 3-state outputs, designed for asynchronous two-way data bus communication. The 74VHC164MTCX is an 8-bit serial-in/parallel-out shift register with a synchronous clear function. They serve fundamentally different logic functions and are not pin-to-pin or function-to-function replacements.
Are the 74VHC245FT and 74VHC164MTCX pin-compatible?
No. The 74VHC245FT is typically supplied in a TSSOP-20 package with a pinout optimized for bidirectional data flow (direction control, output enable, and eight I/O pins). The 74VHC164MTCX is supplied in a TSSOP-14 package with a pinout for serial data inputs, clock, clear, and eight parallel outputs. Package size, pin count, and pin functions differ, so they cannot be interchanged on the same PCB footprint.
Can the 74VHC245FT be used to drive a parallel data bus while the 74VHC164MTCX handles serial-to-parallel conversion in the same design?
Yes, they can coexist in a system because they perform complementary functions. The 74VHC164MTCX can convert serial data into parallel form, and the 74VHC245FT can then buffer or route that parallel data onto a shared bus. However, the system designer must verify voltage compatibility, timing, and drive strength against the respective datasheets.
What are the operating voltage ranges for the 74VHC245FT and 74VHC164MTCX?
Both devices are members of the VHC family and are specified for a supply voltage range of 2.0 V to 5.5 V. This allows operation in 3.3 V and 5 V logic systems, but all input and output voltage levels must remain within the recommended operating conditions listed in the manufacturer datasheets.
Do both devices have 3-state outputs?
No. The 74VHC245FT has 3-state outputs controlled by an output enable pin, allowing the transceiver to be disconnected from the bus. The 74VHC164MTCX has standard push-pull parallel outputs and does not provide a high-impedance state; its outputs are either HIGH or LOW depending on the shift register contents.
Which device is suitable for serial-to-parallel data conversion?
The 74VHC164MTCX is the correct choice for serial-to-parallel conversion. It accepts serial data on two inputs, shifts on the rising edge of the clock, and presents eight parallel outputs. The 74VHC245FT does not perform serial-to-parallel conversion; it only provides bidirectional buffering between two buses.
Are the 74VHC245FT and 74VHC164MTCX available in the same package type?
No. The 74VHC245FT is commonly offered in a 20-pin TSSOP package, while the 74VHC164MTCX is commonly offered in a 14-pin TSSOP package. Package type, pin count, and thermal characteristics differ, so PCB layout and assembly processes must be designed accordingly.
Can the 74VHC245FT replace the 74VHC164MTCX in an existing design without modification?
No. Because the two devices have different logic functions, pin counts, pinouts, and package sizes, a direct replacement is not possible. Any substitution would require a complete redesign of the circuit, including signal routing, control logic, and PCB footprint.