Part A
74VHC244FT
東芝セミコンダクター・アンド・ストレージ
- Lifecycle
- Active
- Stock
- 2156 個数
- Package
- TSSOP-20
- Series
- ロジック - バッファ、ドライバ、レシーバ、トランシーバ
Replacement verdict
Not a drop-in replacement
The 74VHC244FT and 74VHC164MTCX are not functionally interchangeable despite sharing the 74VHC logic family and similar supply voltage characteristics. The 74VHC244FT is an octal non-inverting buffer/line driver with 3-state outputs, while the 74VHC164MTCX is an 8-bit serial-in/parallel-out shift register. Their fundamental logic functions, pin configurations, and I/O architectures differ completely, making direct substitution impossible without circuit redesign.
Different logic function
Different output type
Different pinout
Different data flow
Parts at a glance
Part B
74VHC164MTCX
オンセミコンダクター社
- Lifecycle
- Active
- Stock
- 2495 個数
- Package
- TSSOP-14
- Series
- ロジック - シフトレジスタ
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 | 74VHC164MTCX | Why it matters |
|---|---|---|---|
| Logic Function | Octal Buffer/Line Driver with 3-State Outputs | 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 and cannot substitute for one another. |
| Number of Pins | 20 | 14 | Pin count affects PCB footprint and package compatibility; different pin counts mean the parts are not drop-in replacements. |
| Package Type | TSSOP-20 | TSSOP-14 | Package type and body size must match for physical board assembly and thermal characteristics. |
| Output Type | 3-State | Push-Pull | 3-state outputs allow bus sharing and high-impedance disconnection, while push-pull outputs cannot be tied together, affecting system architecture. |
| Input/Output Direction | Unidirectional (buffered) | Serial input, parallel output | Data flow direction and format determine how the device interfaces with surrounding circuitry. |
| Clock Requirement | No clock (combinational) | Clocked (serial shift) | Clocked devices require a timing signal and introduce sequential behavior, whereas combinational buffers respond immediately to inputs. |
| Supply Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | Both parts operate over the same VHC supply range, so voltage compatibility is not a differentiator. |
| Logic Family | VHC (Very High Speed CMOS) | VHC (Very High Speed CMOS) | Same logic family ensures comparable speed, drive strength, and input/output threshold characteristics. |
| Propagation Delay (typical) | ~3.8 ns at 5 V | ~6.0 ns at 5 V | Propagation delay affects maximum operating frequency and timing margins in synchronous systems. |
| Output Drive Current | ±8 mA | ±8 mA | Drive current determines fan-out capability and ability to drive loads such as LEDs or transmission lines. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC244FT | 74VHC164MTCX |
|---|---|---|
| Supplier | - | onsemi |
| Series | 74VHC | 74VHC |
| Part Status | Active | Active |
| Logic Type | Buffer, Non-Inverting | Shift Register |
| Output Type | 3-State | Push-Pull |
| Number of Elements | 2 | 1 |
| Number of Bits per Element | 4 | 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 74VHC244FT and the 74VHC164MTCX?
The 74VHC244FT is an octal non-inverting buffer/line driver with 3-state outputs, designed for signal buffering and bus driving. The 74VHC164MTCX is an 8-bit serial-in/parallel-out shift register. They serve fundamentally different logic functions and are not interchangeable.
Are the 74VHC244FT and 74VHC164MTCX pin-compatible?
No. The 74VHC244FT is typically supplied in a TSSOP-20 package with 20 pins, while the 74VHC164MTCX is supplied in a TSSOP-14 package with 14 pins. The pin counts and pin functions differ, so they cannot be used as drop-in replacements for each other.
What is the operating voltage range for both devices?
Both the 74VHC244FT and 74VHC164MTCX are members of the VHC logic family and operate over a recommended supply voltage range of 2.0 V to 5.5 V, with typical operation at 3.3 V or 5 V.
Can the 74VHC244FT be used to drive a bus while the 74VHC164MTCX shifts data?
Yes. The 74VHC244FT features 3-state outputs suitable for bus driving, while the 74VHC164MTCX performs serial-to-parallel data conversion. In a system, the shift register can serialize or deserialize data, and the buffer can drive the resulting signals onto a shared bus.
Do both devices support the same output drive current?
Both devices typically provide ±8 mA output drive at 5 V VCC, which is standard for the VHC family. However, the 74VHC244FT has 3-state outputs, whereas the 74VHC164MTCX has standard push-pull parallel outputs without 3-state capability.
Which device is better suited for serial data transmission applications?
The 74VHC164MTCX is better suited for serial data transmission because it is an 8-bit serial-in/parallel-out shift register. The 74VHC244FT is a buffer/driver and does not perform serial-to-parallel conversion.
Are the 74VHC244FT and 74VHC164MTCX available in the same package type?
No. The 74VHC244FT is commonly offered in TSSOP-20, while the 74VHC164MTCX is commonly offered in TSSOP-14. Package types and pin counts differ, so PCB footprints are not compatible.
Can these two devices be used together in the same design?
Yes. They can be used together because they perform complementary functions. The 74VHC164MTCX can shift data in or out, and the 74VHC244FT can buffer or drive the resulting signals, provided the system logic and timing requirements are met.