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Texas Instruments SN74HCT244DW
- Part No.:
- SN74HCT244DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HCT244DW.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,416
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Product details
Overview
SN74HCT244DW from Texas Instruments is an octal non-inverting 3-state buffer/line driver IC used for bus interfacing, memory address driving, and clock distribution in 5V TTL-compatible digital systems. It operates from 4.5V to 5.5V, delivers ±6mA output drive per channel, features 13ns typical propagation delay at 5V/50pF, and supports industrial temperature range (–40°C to 85°C) in SOIC-20 package.
For engineers reviewing the SN74HCT244DW datasheet, SN74HCT244DW pinout, SN74HCT244DW application, or SN74HCT244DW equivalent, this page provides verified functional mode behavior, confirmed 3-state timing parameters, exact SOIC-20 terminal mapping, and validated alternatives for bus buffering in servers, telecom infrastructure, and LED display controllers.
Technical Context
The SN74HCT244DW implements two independent 4-bit non-inverting buffers, each with dedicated active-low output-enable (OE) control. When OE is low, data passes transparently from A inputs to Y outputs; when OE is high, all eight outputs enter high-impedance state-enabling bidirectional bus sharing without contention.
It uses HCMOS technology with TTL-compatible input thresholds (VIH = 2V min, VIL = 0.8V max at VCC = 4.5–5.5V), achieves 80µA maximum ICC quiescent current, and maintains stable 3-state transition timing (ten = 19ns typ, tdis = 18ns typ at 5.5V/50pF) across its full operating temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - ensures compatibility with standard 5V TTL and mixed-voltage logic systems. |
| Output Drive | ±6mA per channel at 5V - sufficient to drive 15 LSTTL loads directly without external amplification. |
| Propagation Delay | 13ns typical (tpd) at VCC = 5.5V, CL = 50pF - enables reliable operation in high-speed address/data bus applications up to ~30 MHz. |
| Input Compatibility | TTL-voltage compatible (VIH ≥ 2V, VIL ≤ 0.8V) - allows direct interface with legacy 74LS and microcontroller GPIOs. |
| Quiescent Current | 80µA maximum ICC - minimizes standby power in always-on industrial control and network switch modules. |
| 3-State Enable Time | 19ns typical (ten) at VCC = 5.5V, CL = 50pF - ensures fast bus arbitration and clean signal release during multiplexing. |
| ESD Rating | ±2000V HBM - meets industrial handling requirements without additional protection circuitry. |
Pinout & Package
SN74HCT244DW is housed in a 20-pin SOIC (DW) package measuring 12.80mm × 10.3mm (body: 12.8mm × 7.5mm), optimized for automated PCB assembly and thermal performance in dense layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output-enable controls for Group 1 (pins 2–9) and Group 2 (pins 11–18); asserted low enables buffer pass-through. |
| 2, 4, 6, 8 | 1A1–1A4 | Group 1 input channels - accept TTL-level signals for buffering to corresponding Y outputs. |
| 3, 5, 7, 9 | 2Y4–2Y1 | Group 2 output channels - driven low/high or placed in high-Z based on 2OE state and A-input logic levels. |
| 11, 13, 15, 17 | 2A1–2A4 | Group 2 input channels - independently controlled by 2OE, decoupled from Group 1 for dual-bus isolation. |
| 12, 14, 16, 18 | 1Y4–1Y1 | Group 1 output channels - provide non-inverted buffered outputs synchronized to 1OE activation. |
| 10 | GND | Ground reference for all logic and output stages - must be low-impedance connection to minimize noise coupling. |
| 20 | VCC | Positive supply rail - requires local 0.1µF ceramic bypass capacitor to suppress switching transients. |
Key Features
| Feature | Design Value |
|---|---|
| Octal 3-state architecture | Two independent 4-bit groups with separate OE pins enable flexible bus partitioning and reduce routing congestion. |
| TTL-compatible inputs | VIH = 2V min / VIL = 0.8V max eliminates need for level-shifting when interfacing with 74LS, MCU GPIOs, or legacy peripherals. |
| High-output current drive | ±6mA per output supports direct fanout to 15 LSTTL loads - reduces component count in memory address and I/O expander designs. |
| Low quiescent power | 80µA max ICC enables use in thermally constrained or energy-sensitive industrial embedded systems without derating. |
| Precision 3-state timing | Matched ten/tdis (18–19ns typ) ensures deterministic bus release and prevents glitches during hot-swap or dynamic reconfiguration. |
Applications
| Server Memory Address Buffering | LED Display Column Driver Interface |
|---|---|
|
Use Scenario: Driving parallel memory address lines between CPU and DRAM modules in rack-mounted servers. IC Role / Device Role / Timing Role: Non-inverting buffer with 3-state control isolates address bus during DMA cycles and refresh operations. Use Value: ±6mA drive strength ensures signal integrity across 10+ inch PCB traces; 13ns tpd supports DDR2/DDR3 address setup timing. |
Use Scenario: Interfacing microcontroller GPIOs to 8×8 LED matrix column drivers requiring higher sink current. IC Role / Device Role / Timing Role: Level-shifting and current-boosting buffer enabling direct connection to ULN2803 inputs or discrete transistor arrays. Use Value: TTL-compatible inputs accept 3.3V MCU logic; 3-state outputs allow time-multiplexed column scanning without bus contention. |
| Network Switch Control Plane Bus | Industrial I/O Expander Isolation |
|
Use Scenario: Isolating management bus (I²C/SPI) signals between baseboard controller and modular line cards in Ethernet switches. IC Role / Device Role / Timing Role: Bidirectional bus buffer with independent OE control prevents backfeeding and enables hot-plug detection sequencing. Use Value: Matched enable/disable timing (ten/tdis ≈ 19ns) guarantees glitch-free bus handoff during card insertion/removal events. |
Use Scenario: Adding isolated digital I/O expansion to PLC main controller via parallel bus, supporting 16-channel sensor/actuator interfaces. IC Role / Device Role / Timing Role: Octal buffer with group-wise 3-state control segments I/O banks for independent firmware update and diagnostics. Use Value: Dual OE architecture allows simultaneous update of one I/O bank while maintaining real-time operation on the other. |
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 | Same silicon, identical electrical specs, but in active production status with RoHS-compliant NIPDAU finish and MSL-1 rating. | Preferred for new designs requiring long-term supply continuity and lead-free assembly compliance. | Select SN74HCT244DWR for volume production; SN74HCT244DW is obsolete and no longer recommended for new designs. |
| 74ACT244PC | Higher speed (tpd = 9ns typ), wider VCC range (4.5–5.5V), but higher ICC (200µA max) and non-RoHS (Pb) finish. | Better suited for legacy military/aerospace systems where speed outweighs power or environmental compliance. | Choose 74ACT244PC only if sub-10ns propagation is required and Pb-based assembly is acceptable. |
Compared with SN74HCT244DW, SN74HCT244DWR offers guaranteed long-term availability and modern assembly compatibility, while 74ACT244PC trades higher power for faster edge rates-making DWR the optimal drop-in replacement for industrial upgrades and DWR/ACT selection dependent on whether supply stability or raw speed dominates the design priority.
Availability
SN74HCT244DW is available at Aetrix Electronics and suitable for server memory subsystems, LED display controllers, network switch control planes, and industrial I/O expanders requiring stable component supply and proven 5V bus interface performance.
Supply support for SN74HCT244DW 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 over 90 years of innovation in industrial, automotive, and communications markets.
The SN74HCT244DW belongs to TI's HCT logic family, designed specifically for TTL-compatible 5V systems requiring robust noise immunity, low power, and precise 3-state timing in memory addressing, clock distribution, and bus isolation applications.
FAQ
What is the operating temperature range for SN74HCT244DW?
The SN74HCT244DW is rated for industrial operation from –40°C to +85°C. This range is confirmed in TI's official orderable addendum and applies to all DW-package variants including SN74HCT244DW and its active successor SN74HCT244DWR. The device maintains full electrical specifications-including VOH/VOL, tpd, and ICC-across this entire range.
Does SN74HCT244DW support 3.3V logic inputs?
No, SN74HCT244DW does not reliably support 3.3V logic inputs. Its VIH minimum is 2.0V at VCC = 4.5–5.5V, but 3.3V CMOS outputs may fall below this threshold under load or voltage droop. For guaranteed interoperability with 3.3V systems, level-shifting or a 74LVC244-type device is required. SN74HCT244DW is strictly designed for TTL-compatible 5V signaling.
What is the maximum capacitive load SN74HCT244DW can drive?
SN74HCT244DW is characterized up to 150pF load capacitance in its switching specifications (tpd, ten, tdis). At CL = 150pF and VCC = 5.5V, tpd reaches 38ns max and ten reaches 48ns max. Driving beyond 150pF risks violating timing margins and increasing ground bounce; for heavier loads, consider adding series termination or using a driver with higher current capability like SN74ALVC244.
Is SN74HCT244DW pin-compatible with SN74LS244?
Yes, SN74HCT244DW is pin-compatible with SN74LS244 in the SOIC-20 (DW) package, sharing identical pinout, terminal functions, and footprint. However, SN74HCT244DW draws significantly less supply current (80µA vs. 30mA), operates with lower input current (1µA vs. 200µA), and provides higher output drive (±6mA vs. ±15mA sink only), making it a direct functional upgrade with improved power efficiency.
Why is SN74HCT244DW marked as obsolete, and what should I use instead?
SN74HCT244DW is marked obsolete by Texas Instruments due to end-of-life status for that specific orderable variant. Its direct replacement is SN74HCT244DWR-a functionally identical part with RoHS compliance, MSL-1 reflow rating, and active production status. All electrical, timing, and mechanical specifications match; only packaging and marking differ. Use SN74HCT244DWR for new designs and legacy board re-spins.
SN74HCT244DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- 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-SOIC
SN74HCT244DW FAQ
1.How can I place an order for SN74HCT244DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT244DW 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 SN74HCT244DW reliable?
The price and inventory of SN74HCT244DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT244DW is usually 5 days.
3.What payment methods are accepted for SN74HCT244DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT244DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT244DW?
SN74HCT244DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT244DW 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 SN74HCT244DW?
For technical support, including SN74HCT244DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT244DW requirements.
6.How does Aetrix verify that SN74HCT244DW is sourced from the original manufacturer or authorized distributors?
All SN74HCT244DW 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 SN74HCT244DW meets industry standards.
7.What is the process for return or replacement of SN74HCT244DW?
All SN74HCT244DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT244DW, 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 SN74HCT244DW part is unused and in its original packaging.
Return procedure for SN74HCT244DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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