Part A
74VHC245FT
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 4188 PCS
- Package
- TSSOP-20
- Series
- Logic - Buffers, Drivers, Receivers, Transceivers
Replacement verdict
Not a drop-in replacement
The 74VHC245FT and 74VHC164FT are not functionally interchangeable despite sharing the same VHC logic family and TSSOP-20 package. The 74VHC245FT is an octal bidirectional transceiver with 3-state outputs and direction control, while the 74VHC164FT is an 8-bit serial-in/parallel-out shift register. Their differing logic functions, pin assignments, and control interfaces make direct substitution impossible without circuit redesign.
Different logic function
Different pinout
Different control interface
Different output behavior
Parts at a glance
Part B
74VHC164FT
Toshiba Semiconductor and Storage
- Lifecycle
- Active
- Stock
- 2549 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 | 74VHC164FT | Why it matters |
|---|---|---|---|
| Function | Octal bidirectional transceiver with 3-state outputs | 8-bit serial-in/parallel-out shift register | Defines the core logic function; these devices are not functionally interchangeable. |
| Logic Type | Bus transceiver | Shift register | Determines how data is transferred and latched within a system. |
| Number of Circuits / Bits | 8-bit (octal) | 8-bit | Both handle 8 bits, but the internal data path architecture differs. |
| Direction Control | Direction pin (DIR) selects A-to-B or B-to-A | Not applicable; data flows serially in one direction | Bidirectional capability is essential for bus interfacing, which the shift register cannot provide. |
| Output Type | 3-state (tri-state) outputs | Push-pull parallel outputs | 3-state outputs allow bus sharing; push-pull outputs are always driven. |
| Clock Requirement | No clock; combinational logic | Requires clock for shifting | Clock dependency affects timing, synchronization, and control logic design. |
| Input / Output Configuration | Dual 8-bit ports (A and B) with direction control | Serial input (A/B) and 8 parallel outputs (QA-QH) | Pin function and signal flow differ completely, preventing direct substitution. |
| Typical Application | Bus driving, level shifting, bidirectional data transfer | Serial-to-parallel conversion, LED driving, data expansion | Application context determines whether the device fits the intended circuit role. |
| Supply Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | Both operate over the same VHC logic supply range, allowing use in similar voltage systems. |
| Package | TSSOP-20 | TSSOP-14 | Different pin counts and footprints affect PCB layout and cannot be interchanged without redesign. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 74VHC245FT | 74VHC164FT |
|---|---|---|
| Supplier | - | Toshiba Semiconductor and Storage |
| Series | 74VHC | TC74VHC |
| 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 74VHC164FT?
The 74VHC245FT is an octal bidirectional transceiver with 3-state outputs, designed for asynchronous two-way data transfer between buses. The 74VHC164FT is an 8-bit serial-in/parallel-out shift register with a synchronous clear function. They serve fundamentally different logic functions and are not interchangeable.
Do the 74VHC245FT and 74VHC164FT share the same package and pinout?
Both devices are offered in the TSSOP-20 package (suffix FT typically denotes TSSOP-20 for Toshiba VHC series). However, their pinouts differ because their internal logic functions are different. The 74VHC245FT has direction control (DIR) and output enable (OE) pins, while the 74VHC164FT has serial data inputs (A, B), clock (CK), and clear (CLR) pins.
Can the 74VHC245FT and 74VHC164FT operate at the same supply voltage range?
Yes. Both devices are members of the 74VHC family and typically operate over a supply voltage range of 2.0 V to 5.5 V, with guaranteed characteristics at 5.0 V ± 0.5 V. Always verify the specific datasheet for the exact recommended operating conditions.
Are the 74VHC245FT and 74VHC164FT pin-to-pin compatible with older 74HC or 74HCT equivalents?
Functionally, the 74VHC245FT is pin-compatible with standard 74HC245/74HCT245 devices in the same package. The 74VHC164FT is pin-compatible with standard 74HC164/74HCT164 devices. However, VHC devices have different input thresholds and drive characteristics compared to HCT, so direct substitution requires validation of logic-level compatibility in the target design.
What is the maximum operating frequency of the 74VHC164FT shift register?
The 74VHC164FT typically supports a maximum clock frequency of 115 MHz at 5.0 V supply and 25°C, according to Toshiba datasheet specifications. This parameter is dependent on supply voltage and load conditions; consult the official datasheet for derating information.
What is the output drive capability of the 74VHC245FT compared to the 74VHC164FT?
Both devices typically provide ±8 mA output drive at 5.0 V supply voltage. The 74VHC245FT has 3-state outputs that can be placed in high-impedance mode, while the 74VHC164FT has standard push-pull parallel outputs without 3-state capability.
Can the 74VHC245FT be used to drive a bus that the 74VHC164FT reads from?
Yes, in principle. The 74VHC245FT can drive a parallel bus with its 3-state outputs, and the 74VHC164FT can accept parallel data only if it is configured for parallel load, which the standard 74VHC164FT does not support. The 74VHC164FT is a serial-in/parallel-out device, so it cannot directly read a parallel bus without external serialization.
Are the 74VHC245FT and 74VHC164FT qualified to the same automotive or industrial standards?
Qualification depends on the specific manufacturer part number and suffix. Toshiba offers both devices in standard commercial/industrial grades. Automotive-qualified versions may exist under different ordering codes. Verify the exact ordering part number against the manufacturer's qualification report; do not assume identical qualification based on the base part number alone.