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Texas Instruments SN74AS244ADW
- Part No.:
- SN74AS244ADW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74AS244ADW.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,497
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Product details
Overview
SN74AS244ADW from Texas Instruments is an octal non-inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving in TTL-compatible systems. It operates from 4.5 V to 5.5 V, delivers ±15 mA high-level and 64 mA low-level output current, and features pnp inputs to reduce DC loading. It is used in industrial control backplanes and legacy data acquisition systems requiring robust bus isolation.
For engineers reviewing the SN74AS244ADW datasheet, SN74AS244ADW pinout, SN74AS244ADW application, or SN74AS244ADW equivalent, this page provides verified electrical specs, DW-package terminal mapping, real-world use cases, and two validated alternative parts for design continuity and sourcing flexibility.
Technical Context
The SN74AS244ADW implements dual 4-bit non-inverting buffers with independent 3-state enable controls (1OE, 2OE), each managing four outputs (Y1–Y4 per side). Its AS-family logic uses advanced Schottky TTL architecture for improved speed over ALS variants, with propagation delays as low as 1 ns (tPHL) and enable/disable times under 10 ns.
It supports bidirectional bus interfacing via high-impedance output states, features input clamping diodes (VIK = –1.2 V), and maintains stable VOH ≥ 2.4 V at IOH = –15 mA and VOL ≤ 0.55 V at IOL = 64 mA - critical for noise margin preservation in dense PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL power rails and tolerance against supply ripple. |
| IOL (max) | 64 mA - enables direct drive of heavy capacitive loads (e.g., >100 pF buses) without external buffering. |
| tPHL / tPLH | 1 ns / 2 ns - supports high-speed address latching in microprocessor-based systems up to ~100 MHz clock domains. |
| VIK (Input Clamp) | –1.2 V - protects inputs from negative transients and allows safe interfacing with open-collector sources. |
| ICC (Outputs Low) | 90 mA - defines worst-case power dissipation (450 mW at 5 V), guiding thermal layout and decoupling design. |
| Operating Temp | 0°C to 70°C - qualified for commercial-grade embedded systems, not extended industrial or automotive environments. |
| Package | SOIC-20 (DW) - 7.5 mm × 12.8 mm footprint with 1.27 mm pitch, compatible with standard surface-mount reflow profiles (MSL Level-1). |
Pinout & Package
SN74AS244ADW is housed in a 20-pin SOIC (DW) package with 1.27 mm lead pitch, 7.5 mm body width, and 2.65 mm maximum height. Pin 1 is located at the top-left corner with a beveled edge marker.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE (Active-Low Enable) | Independent 3-state control for first and second buffer groups; low = outputs enabled, high = high-Z. |
| 2–5, 13–16 | 1A1–1A4, 2A1–2A4 (Inputs) | Non-inverting data inputs; pnp-coupled to reduce input current loading on driving sources. |
| 6–9, 11–14 | 1Y1–1Y4, 2Y1–2Y4 (Outputs) | Buffered, 3-state outputs capable of sinking 64 mA or sourcing 15 mA with rail-to-rail swing. |
| 10 | GND | Ground reference for all logic and output stages; requires low-inductance connection to minimize switching noise. |
| 20 | VCC | Positive supply; must be decoupled locally with ≥0.1 µF ceramic capacitor near pin 20. |
Key Features
| Feature | Design Value |
|---|---|
| 3-State Output Control | Two independent active-low OE inputs allow selective enabling of either 4-bit buffer bank, enabling time-multiplexed bus sharing. |
| pnp Input Structure | Reduces input current to ≤ –1 mA (IIL), minimizing loading on upstream logic and improving fan-out capability. |
| High Sink Current | 64 mA per output supports direct interface to LEDs, relays, or terminated transmission lines without external drivers. |
| Fast Enable/Disable | tPZL ≤ 7.5 ns and tPHZ ≤ 6 ns ensure minimal bus contention during state transitions in multi-master systems. |
| TTL-Compatible Thresholds | VIH = 2.0 V and VIL = 0.8 V guarantee interoperability with standard 74LS/74F and microcontroller GPIOs. |
Applications
| Memory Address Buffering | Industrial Backplane Interface |
|---|---|
|
Use Scenario: Driving 20-bit address bus between microcontroller and SRAM/ROM in a PLC mainboard. IC Role / Device Role / Timing Role: Non-inverting buffer isolating CPU address lines from memory module capacitance and noise. Use Value: 64 mA sink capability ensures clean signal edges across 15 cm traces; 3-state enables shared bus arbitration with DMA controller. |
Use Scenario: Interfacing multiple I/O modules to a central controller via parallel backplane with daisy-chained enable signals. IC Role / Device Role / Timing Role: Bus driver providing level-shifting and current gain between controller logic and module-side receivers. Use Value: Dual OE pins allow staggered activation of I/O banks, reducing simultaneous switching noise (SSN) on shared VCC/GND planes. |
| Data Acquisition Multiplexing | Legacy Instrumentation Bus |
|
Use Scenario: Selecting analog front-end channels using digital control lines routed through a buffered address decoder. IC Role / Device Role / Timing Role: Signal integrity enhancer for low-skew address selection in 16-channel DAQ system. Use Value: 2 ns max tPLH ensures <10 ns address setup margin for 50 MHz sampling clocks; VIH/VIL tolerances accommodate aging CMOS drivers. |
Use Scenario: Replacing obsolete 74LS244 in test equipment where firmware expects TTL-level handshake timing. IC Role / Device Role / Timing Role: Drop-in performance upgrade delivering faster propagation and higher drive strength without board redesign. Use Value: Identical pinout and logic function to SN74LS244, but with 3× lower propagation delay and 2× higher IOL - extends system lifetime without hardware change. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS244AN | Same AS-family logic, identical electrical specs, but in PDIP-20 package (10.16 mm width, through-hole mount). | Suitable for prototyping, repair, or legacy through-hole assemblies; lacks RoHS-compliant NiPdAu finish. | Select when manual soldering, socketing, or thermal mass requirements favor DIP over SOIC. |
| SN74ALS244CDWR | ALS-family variant: lower IOL (24 mA), slower tPHL (3 ns), reduced ICC (24 mA), same pinout and voltage specs. | Better suited for low-power, noise-sensitive applications where 64 mA drive is unnecessary. | Choose for cost-sensitive designs with marginal load requirements and tighter power budgets. |
Compared with SN74AS244ADW, SN74AS244AN offers identical performance in through-hole format for legacy compatibility, while SN74ALS244CDWR trades drive strength and speed for lower power and cost - enabling optimization based on board assembly method and system-level current demands.
Availability
SN74AS244ADW is available at Aetrix Electronics and suitable for industrial control backplanes, legacy instrumentation interfaces, and memory subsystems requiring stable component supply and long-term obsolescence management.
Supply support for SN74AS244ADW 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 TTL and advanced logic families.
The SN74AS244ADW belongs to TI's 74AS logic series - engineered for high-speed, high-drive applications in industrial and computing infrastructure where reliability and deterministic timing are critical.
FAQ
What is the maximum operating temperature range for SN74AS244ADW?
The SN74AS244ADW is characterized for operation from 0°C to 70°C, meeting commercial-grade temperature specifications. It is not rated for extended industrial (–40°C to 85°C) or military (–55°C to 125°C) ranges. Thermal derating is required above 70°C ambient, and sustained operation outside this range may cause parametric shift or failure.
Does SN74AS244ADW support true bidirectional data flow?
No - SN74AS244ADW is a unidirectional non-inverting buffer with fixed input-to-output direction (A → Y). Bidirectional operation requires external control logic and complementary transceivers like the SN74AS245. The 3-state outputs enable bus sharing but do not reverse signal path direction.
Can SN74AS244ADW be used as a level shifter between 3.3 V and 5 V logic?
SN74AS244ADW is not a level shifter: its inputs require TTL-compatible thresholds (VIH = 2.0 V, VIL = 0.8 V), making it compatible with 3.3 V CMOS outputs only if they meet those levels. It cannot translate 3.3 V logic highs to 5 V outputs - output swing is rail-referenced to VCC (5 V), but input recognition does not scale with VCC.
What is the recommended decoupling for SN74AS244ADW?
A minimum of one 0.1 µF X7R ceramic capacitor placed within 3 mm of VCC (pin 20) and GND (pin 10) is required. For systems with multiple SN74AS244ADW devices or high-frequency switching, add a 4.7 µF tantalum or polymer capacitor per 5–10 ICs on the same VCC plane to suppress low-frequency droop.
Is SN74AS244ADW RoHS compliant?
Yes - the active tape-and-reel version SN74AS244ADWR.A is RoHS compliant with NiPdAu lead finish and MSL Level-1 rating. The obsolete SN74AS244ADW (no suffix) is not RoHS compliant and should be avoided for new designs requiring environmental compliance.
SN74AS244ADW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- 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:
- 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74AS244ADW FAQ
1.How can I place an order for SN74AS244ADW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS244ADW 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 SN74AS244ADW reliable?
The price and inventory of SN74AS244ADW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS244ADW is usually 5 days.
3.What payment methods are accepted for SN74AS244ADW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS244ADW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS244ADW?
SN74AS244ADW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS244ADW 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 SN74AS244ADW?
For technical support, including SN74AS244ADW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS244ADW requirements.
6.How does Aetrix verify that SN74AS244ADW is sourced from the original manufacturer or authorized distributors?
All SN74AS244ADW 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 SN74AS244ADW meets industry standards.
7.What is the process for return or replacement of SN74AS244ADW?
All SN74AS244ADW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS244ADW, 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 SN74AS244ADW part is unused and in its original packaging.
Return procedure for SN74AS244ADW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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