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Texas Instruments SN74HCT244PWT
- Part No.:
- SN74HCT244PWT
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74HCT244PWT.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,484
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Product details
Overview
SN74HCT244PWT from Texas Instruments is an octal non-inverting 3-state buffer/line driver IC designed for bus-oriented memory address and data line interfacing. It operates at 4.5–5.5 V, delivers ±6 mA output drive per channel, exhibits 13 ns typical propagation delay (at 5.5 V, 50 pF), and supports TTL-compatible inputs. It is used in server backplanes and LED display drivers where high-current buffering with bus contention control is required.
For engineers reviewing the SN74HCT244PWT datasheet, SN74HCT244PWT pinout, SN74HCT244PWT application, or SN74HCT244PWT equivalent, key selection criteria include its 20-pin TSSOP package, dual 4-bit independent enable architecture, 3-state output behavior under OE control, and compatibility with LSTTL load driving (up to 15 units) in industrial-grade temperature range (–40°C to 85°C).
Technical Context
The SN74HCT244PWT implements two independent 4-bit buffer sections (Group 1: A1–A4 → Y1–Y4; Group 2: A1–A4 → Y1–Y4), each controlled by a dedicated active-low output-enable input (1OE, 2OE). Its CMOS HCT logic family ensures TTL voltage-level compatibility while maintaining low static current (≤80 µA ICC).
Each output transitions between low-impedance logic states (driving high/low) and high-impedance tri-state when OE is asserted high. Propagation delay (tpd = 13 ns typ. at 5.5 V, 50 pF) and enable/disable timing (ten/tdis ≤ 48 ns max) are specified across –40°C to 85°C, supporting reliable timing in synchronous bus systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V logic rails and tolerance against supply ripple. |
| Output Drive | ±6 mA per output at 5 V - Sufficient to directly drive 15 LSTTL loads without external amplification. |
| Propagation Delay | 13 ns typical (VCC = 5.5 V, CL = 50 pF) - Enables use in sub-40 MHz bus clock domains with margin. |
| Input Compatibility | TTL-voltage compatible (VIH ≥ 2 V, VIL ≤ 0.8 V) - Interoperates with legacy 5 V TTL and CMOS logic families. |
| Quiescent Current | 80 µA maximum ICC - Minimizes standby power in always-on system interfaces. |
| ESD Rating | ±2000 V HBM - Meets industrial handling robustness requirements per ANSI/ESDA/JEDEC JS-001. |
| Operating Temperature | –40°C to +85°C - Qualified for commercial and extended-temperature industrial applications. |
Pinout & Package
The SN74HCT244PWT is packaged in a 20-pin Thin Shrink Small Outline Package (TSSOP), measuring 6.5 mm × 6.4 mm (body: 6.5 mm × 4.4 mm), with gull-wing leads and RoHS-compliant NiPdAu plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output-enable inputs - Control high-impedance state for respective 4-bit groups; must be pulled low to enable outputs. |
| 2, 4, 6, 8, 11, 13, 15, 17 | 1A1–1A4, 2A1–2A4 | Buffer input terminals - Accept TTL-compatible signals; no internal pull-up/down; require defined logic levels. |
| 3, 5, 7, 9, 12, 14, 16, 18 | 1Y1–1Y4, 2Y1–2Y4 | Non-inverting 3-state outputs - Drive bus lines or memory registers; enter high-Z when corresponding OE is high. |
| 10 | GND | Ground reference - Return path for all input/output currents and internal logic; requires low-impedance PCB connection. |
| 20 | VCC | Power supply - Must be bypassed with 0.1 µF ceramic capacitor placed adjacent to pin to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Independent dual 4-bit enables | Separate 1OE and 2OE pins allow selective activation of two buffer banks - essential for multiplexed address/data buses. |
| High-current 3-state outputs | ±6 mA drive capability per output sustains signal integrity across long PCB traces or capacitive loads up to 150 pF. |
| TTL-compatible input thresholds | VIH ≥ 2.0 V and VIL ≤ 0.8 V ensure seamless interfacing with legacy 5 V microcontrollers, FPGAs, and peripheral ICs. |
| Low quiescent power | 80 µA max ICC enables use in power-sensitive applications such as fanless servers or remote I/O modules. |
| Fast propagation timing | 13 ns typical tpd at 5.5 V allows integration into 25+ MHz synchronous bus architectures with timing margin. |
Applications
| Server Backplane Interface | LED Segment Driver |
|---|---|
Use Scenario: Buffering memory address lines between CPU and multi-slot backplane in rack-mounted servers. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer isolating address bus segments during DMA cycles to prevent contention. Use Value: ±6 mA drive ensures clean edge integrity over 10+ inch FR4 traces; dual OE control enables dynamic segment enable/disable without software overhead. |
Use Scenario: Driving common-anode 7-segment LED displays in industrial HMIs with microcontroller GPIO expansion. IC Role / Device Role / Timing Role: High-current line driver translating low-drive MCU outputs to sink sufficient current for bright LED segments. Use Value: 15 LSTTL load rating directly supports 20 mA per segment; 3-state capability allows multiplexed digit scanning without external transistors. |
| Network Switch ASIC Interface | Industrial I/O Expander |
Use Scenario: Level-shifting and buffering control signals between 3.3 V switch ASIC and 5 V legacy PHY management circuitry. IC Role / Device Role / Timing Role: Voltage-tolerant interface buffer ensuring signal integrity across mixed-voltage domains with no level translation needed. Use Value: TTL-compatible inputs accept 3.3 V logic highs reliably; 13 ns tpd preserves setup/hold margins in 50 MHz control buses. |
Use Scenario: Extending GPIO count of PLC controllers to drive relays, solenoids, and indicator lamps in factory automation. IC Role / Device Role / Timing Role: Robust output buffer providing fault-isolated drive capability for inductive and capacitive industrial loads. Use Value: ±35 mA absolute max output current per pin supports direct relay coil drive; high-Z state prevents backfeed during hot-swap events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT244DWR | SOIC-20 package (12.8 mm × 10.3 mm); same electrical specs; higher thermal resistance (RθJA = 109.1°C/W vs 131.8°C/W). | Better suited for through-hole prototyping or high-reliability industrial boards where TSSOP reflow is not available. | Select when board assembly uses wave soldering or requires larger pitch for manual repair. |
| SN74LVC244APWR | Lower VCC range (1.65–3.6 V); 3.3 V native logic; ±24 mA drive; faster tpd (5.1 ns typ); not TTL-compatible. | Designed for modern low-voltage embedded systems; incompatible with 5 V buses unless level-shifted. | Choose only for new 3.3 V designs requiring higher speed and lower power; not a drop-in replacement for 5 V systems. |
Compared with SN74HCT244DWR and SN74LVC244APWR, the SN74HCT244PWT uniquely balances 5 V TTL interoperability, compact TSSOP footprint, and industrial temperature support - making it optimal for space-constrained 5 V bus interfaces where legacy compatibility is mandatory.
Availability
SN74HCT244PWT is available at Aetrix Electronics and suitable for server backplanes, LED display drivers, and industrial I/O expanders requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN74HCT244PWT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with decades of heritage in high-reliability logic families.
The SN74HCT244PWT belongs to TI's HCT logic series - engineered for TTL-compatible operation in 5 V systems, emphasizing robust noise immunity, predictable timing, and seamless integration with legacy digital infrastructure.
FAQ
What is the operating temperature range for the SN74HCT244PWT?
The SN74HCT244PWT is rated for operation from –40°C to +85°C. This industrial-grade temperature specification is confirmed in TI's official datasheet revision I (February 2025), and applies specifically to the PW (TSSOP) package variant. The device maintains full electrical performance-including propagation delay, output drive, and input thresholds-across this entire range, making SN74HCT244PWT suitable for deployment in uncontrolled ambient environments such as network cabinets and factory floors.
Does the SN74HCT244PWT support true 5 V TTL input compatibility?
Yes, the SN74HCT244PWT features TTL-voltage compatible inputs, with guaranteed VIH ≥ 2.0 V and VIL ≤ 0.8 V over the full 4.5–5.5 V supply range. This allows direct connection to standard 5 V TTL outputs (e.g., 74LS series) without level shifting. The input structure is CMOS-based but biased to recognize TTL logic thresholds-verified in Section 5.3 (Recommended Operating Conditions) of the SN74HCT244 datasheet-and applies identically to SN74HCT244PWT.
What is the maximum capacitive load the SN74HCT244PWT can drive while maintaining timing specifications?
The SN74HCT244PWT's switching characteristics-including tpd (13 ns typ.), ten (19 ns typ.), and tdis (18 ns typ.)-are characterized up to 150 pF load capacitance at 5.5 V supply, per Section 5.8 of the datasheet. Driving loads beyond 150 pF will increase propagation and enable delays nonlinearly and may violate setup/hold timing in high-speed buses. For loads >150 pF, SN74HCT244PWT should be paired with series termination or local buffering.
Can the SN74HCT244PWT be used in hot-swap applications?
The SN74HCT244PWT supports hot-swap operation only when both OE inputs are held high (disabled) during insertion, and VCC is ramped before applying input signals. Its absolute maximum ratings specify no I/O voltage limits beyond GND and VCC, and it lacks powered-off protection. Therefore, SN74HCT244PWT requires external sequencing control-such as pull-up resistors on OE tied to VCC and staggered power ramping-to avoid bus contention or latch-up during live insertion.
Is there a pin-compatible 3.3 V alternative to the SN74HCT244PWT?
No truly pin-compatible 3.3 V alternative exists for SN74HCT244PWT. The SN74LVC244APWR shares the same TSSOP-20 footprint and pinout but operates at 1.65–3.6 V and lacks TTL input compatibility. It cannot accept 5 V inputs safely and requires level shifters in mixed-voltage systems. Thus, SN74HCT244PWT remains the correct choice for 5 V bus interfacing; migration to 3.3 V necessitates redesign, not substitution.
SN74HCT244PWT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
SN74HCT244PWT FAQ
1.How can I place an order for SN74HCT244PWT through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT244PWT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74HCT244PWT reliable?
The price and inventory of SN74HCT244PWT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT244PWT is usually 5 days.
3.What payment methods are accepted for SN74HCT244PWT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT244PWT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT244PWT?
SN74HCT244PWT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT244PWT order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74HCT244PWT?
For technical support, including SN74HCT244PWT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT244PWT requirements.
6.How does Aetrix verify that SN74HCT244PWT is sourced from the original manufacturer or authorized distributors?
All SN74HCT244PWT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74HCT244PWT meets industry standards.
7.What is the process for return or replacement of SN74HCT244PWT?
All SN74HCT244PWT units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT244PWT, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74HCT244PWT part is unused and in its original packaging.
Return procedure for SN74HCT244PWT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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