SN74HCT TTL-Compatible CMOS Logic Variants
Texas Instruments SN74HCT devices provide 5 V CMOS logic with TTL-compatible inputs for gates, buffers, flip-flops, counters, registers, and interface functions.
SN74HCT logic for TTL-input 5 V systems
Compare SN74HCT functions, packages, timing, output drive, and replacement considerations.
The SN74HCT family is Texas Instruments' TTL-compatible version of high-speed CMOS 74 logic. It is used when a 5 V CMOS device must reliably accept input levels from TTL or LS-family outputs. The family includes common gates, inverters, buffers, multiplexers, counters, latches, flip-flops, shift registers, and bus functions in SOIC, TSSOP, SSOP, DIP, and related packages.
SN74HCT is a common choice for legacy redesigns because it preserves TTL input compatibility while reducing static current versus bipolar TTL families. It should not be selected only by truth table. Review input thresholds, output drive, propagation delay, package pinout, output-enable timing, fanout, and whether the original circuit relies on open-collector or bus-hold behavior.
Key Features
- TTL-compatible inputs for 5 V legacy and mixed-logic boards
- CMOS logic option for gates, counters, registers, and buffers
- Useful for reducing static power versus LS TTL where compatible
- Available in service-friendly and compact SMT packages
- Requires exact timing and output topology checks for substitution
Target Applications
- Legacy TTL-to-CMOS logic paths
- Industrial control and I/O boards
- Counter, latch, and register circuits
- Test fixtures and adapters
- 5 V embedded systems
Ordering Variants
Compare 136 SN74HCT part numbers by package, electrical parameters, lifecycle, and availability. Use RFQ for stock and lead-time confirmation.
| Part Number | Description | Package Type | Manufacturer | Lifecycle | RoHS | Availability | Action |
|---|---|---|---|---|---|---|---|
| SN74HCT245N | Package: PDIP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Channels: 8 | Number of Outputs: 8 | Number of Bits: 8 | Logic Function: Transceiver, Inverting | PDIP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT125D | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 6mA | Number of Channels: 4 | Number of Outputs: 4 | Number of Bits: 4 | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT125DR | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Channels: 4 | Number of Outputs: 4 | Number of Bits: 4 | Logic Function: Buffer, Inverting | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT240DW | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Channels: 8 | Number of Outputs: 8 | Number of Bits: 8 | Logic Function: Buffer, Inverter | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT244NSR | Package: SOP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Channels: 8 | Number of Outputs: 8 | Number of Bits: 8 | Logic Function: Buffer, Inverting | SOP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT374DWRG4 | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Outputs: 8 | Number of Bits: 8 | Frequency: 40MHz | Logic Function: D-Type, Flip-Flop | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT377DW | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 4mA | Number of Bits: 8 | Frequency: 37MHz | Max Frequency: 19MHz | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT574DW | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 6mA | Number of Outputs: 8 | Number of Bits: 8 | Frequency: 40MHz | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT574PWR | Package: TSSOP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Outputs: 8 | Number of Bits: 8 | Frequency: 27MHz | Max Frequency: 27MHz | TSSOP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT00DG4 | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 4mA | Number of Outputs: 1 | Number of Bits: 4 | Logic Function: NAND GATE | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT08PWT | Package: TSSOP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 4mA | Max Output Current: 4mA | Number of Outputs: 1 | Number of Bits: 4 | TSSOP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT32N | Package: PDIP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 4mA | Max Output Current: 4mA | Number of Channels: 4 | Number of Outputs: 1 | PDIP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT273DBRE4 | Package: SSOP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Bits: 8 | Frequency: 37MHz | Logic Function: D-Type, Flip-Flop | Max Operating Temp: 85°C | SSOP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT273DWRE4 | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Bits: 8 | Frequency: 37MHz | Logic Function: D-Type, Flip-Flop | Max Operating Temp: 85°C | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT374DBRG4 | Package: SSOP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Outputs: 8 | Number of Bits: 8 | Frequency: 40MHz | Logic Function: D-Type, Flip-Flop | SSOP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT374PWE4 | Package: TSSOP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Outputs: 8 | Number of Bits: 8 | Frequency: 40MHz | Logic Function: D-Type, Flip-Flop | TSSOP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT138D | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 25mA | Number of Channels: 1 | Number of Outputs: 8 | Number of Bits: 8 | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT138DG4 | Package: SOIC | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Channels: 1 | Number of Outputs: 8 | Number of Bits: 8 | Logic Function: Demultiplexer, Decoder | SOIC | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT138N | Package: PDIP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Output Current: 25mA | Number of Channels: 1 | Number of Outputs: 8 | Number of Bits: 8 | PDIP | Texas Instruments | Active | Compliant | In Stock | |
| SN74HCT138PW | Package: TSSOP | Operating Supply Voltage: 5V | Max Supply Voltage: 5.5V | Min Supply Voltage: 4.5V | Number of Channels: 1 | Number of Outputs: 8 | Number of Bits: 8 | Logic Function: Demultiplexer, Decoder | TSSOP | Texas Instruments | Active | Compliant | In Stock |
Ordering Code Differences
How suffixes on SN74HCT map to package, grade, and reel options.
[{"code":"SN74HCT00 / 02 / 04 / 08","meaning":"Common NAND, NOR, inverter, and AND gate functions."},{"code":"SN74HCT74 / 138 / 595","meaning":"Common sequential, decoder, and shift-register variants."},{"code":"HCT vs HC","meaning":"HCT accepts TTL input levels; HC expects CMOS input levels."},{"code":"D, N, PW, DB suffixes","meaning":"Package and packing identifiers such as SOIC, PDIP, TSSOP, or SSOP."}]
How to Choose the Right SN74HCT Drivers, Receivers and Transceivers
Confirm input source
Use HCT when the driving output is TTL-level; use HC when signals are CMOS-level.
Check output compatibility
Output drive and edge rate can differ from LS or ALS parts.
Watch asynchronous paths
Propagation delay changes can affect counters, resets, and decode logic.
Technical Specifications
Core parameters for SN74HCT product family
Source SN74HCT with Octatronics
Request stock confirmation, lead time, date code, and pricing for all 136 ordering variants from Texas Instruments. Our team supports active, EOL, and hard-to-find component sourcing.
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Frequently Asked Questions
Common technical questions about the SN74HCT product family.