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Texas Instruments SN74AS244ADWR
- Part No.:
- SN74AS244ADWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74AS244ADWR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,036
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Product details
Overview
SN74AS244ADWR 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 output drive, supports 0°C to 70°C industrial temperature range, and features low propagation delay (tPLH/tPHL ≤ 6.2 ns) in SOIC-20 package - used in legacy industrial control backplanes and parallel data buses.
For engineers reviewing the SN74AS244ADWR datasheet, SN74AS244ADWR pinout, SN74AS244ADWR application, or SN74AS244ADWR equivalent, this page provides verified electrical specs, functional truth table, package dimensions, real-world use cases in bus isolation and address buffering, and two validated alternative parts with documented differences in drive strength and timing.
Technical Context
The SN74AS244ADWR implements eight independent non-inverting buffers, each with separate 3-state enable control via dual active-low OE inputs (1OE, 2OE), allowing half-bus (4-bit) granularity. Its AS-family architecture uses advanced Schottky TTL logic for higher speed and lower power than standard TTL.
Each buffer exhibits symmetrical input thresholds (VIH = 2 V, VIL = 0.8 V), rail-to-rail output swing (VOH ≥ 2.4 V at IOL = 15 mA), and fast enable/disable transitions (tPZL ≤ 7.5 ns, tPHZ ≤ 6 ns), making it suitable for dynamic bus arbitration in synchronous digital systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL rails; no external regulation required. |
| Output Drive (IOL) | 64 mA max - enables direct drive of multiple TTL loads or termination-resistor networks without external buffers. |
| Propagation Delay | ≤ 6.2 ns (A→Y, VCC = 5 V, CL = 50 pF) - supports >100 MHz bus toggle rates in short-trace applications. |
| Enable/Disable Time | tPZL ≤ 7.5 ns, tPHZ ≤ 6 ns - ensures clean bus release before next cycle, critical for shared-memory arbitration. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL logic levels; interoperable with 74LS, 74ALS, and microcontroller GPIOs. |
| Operating Temperature | 0°C to 70°C - qualified for commercial/industrial ambient environments, not extended or military grade. |
| Package | SOIC-20 (DW), 7.5 mm × 12.8 mm - surface-mount compatible with automated assembly; RoHS-compliant NIPDAU finish. |
Pinout & Package
SN74AS244ADWR is housed in a 20-pin SOIC (DW) package per JEDEC MS-013, with 1.27 mm pitch, 2.65 mm max height, and gull-wing leads. Pin 1 is located at the top-left corner with notch or index mark.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE (Active-Low Output Enable) | Independent enables for first/second group of four buffers; low = outputs active, high = high-impedance. |
| 2–5, 13–16 | 1A1–1A4, 2A1–2A4 (Inputs) | Eight buffered data inputs; pnp-input structure reduces DC loading on driving sources. |
| 6–9, 11–14 | 1Y1–1Y4, 2Y1–2Y4 (Outputs) | Non-inverting 3-state outputs; capable of sinking 64 mA or sourcing 15 mA while maintaining VOH/VOL specs. |
| 10 | GND | Ground reference for all logic and output stages; requires low-inductance connection to minimize switching noise. |
| 20 | VCC | +5 V supply; decoupling capacitor (0.1 µF ceramic) recommended within 5 mm of pin for stable operation. |
Key Features
| Feature | Design Value |
|---|---|
| Octal 3-State Buffer Architecture | Two independent 4-bit groups with dedicated OE pins - enables partial bus control without full-system reset. |
| AS-Series Speed-Power Tradeoff | 6.2 ns propagation delay with 90 mA max ICC - faster than ALS family while maintaining TTL compatibility. |
| pnp Input Structure | Reduces input current draw (IIL = –1 mA max) - lowers loading on upstream drivers like microcontroller ports or FPGA I/O banks. |
| High Sink Current Capability | 64 mA per output - drives 10+ standard TTL loads or terminates 50 Ω transmission lines directly. |
| SOIC-20 RoHS Compliance | NIPDAU lead finish, MSL Level-1, 260°C peak reflow - supports lead-free manufacturing and long-term supply continuity. |
Applications
| Memory Address Buffering | Parallel Bus Isolation |
|---|---|
|
Use Scenario: Driving 16-bit address lines from a microprocessor to multiple memory ICs on a shared bus. IC Role / Device Role / Timing Role: Non-inverting buffer with 3-state control isolates CPU address outputs during DMA cycles or peripheral access. Use Value: Prevents bus contention by enabling/disabling address drivers synchronously with memory select signals, eliminating need for external bus transceivers. |
Use Scenario: Interfacing a microcontroller's parallel port to an external LCD module or printer interface. IC Role / Device Role / Timing Role: Bidirectional bus driver with independent OE control manages data flow direction and timing alignment. Use Value: Eliminates external direction-control logic; 6.2 ns delay ensures setup/hold compliance with 8-bit peripherals operating up to 16 MHz. |
| Legacy Industrial Backplane | TTL-Level Signal Translation |
|
Use Scenario: Replacing failed 74LS244 units in aging PLC I/O modules requiring drop-in compatibility. IC Role / Device Role / Timing Role: Pin-compatible TTL buffer with enhanced drive strength and speed for field-replacement upgrades. Use Value: Maintains existing PCB layout while improving signal integrity on long backplane traces due to 64 mA sink capability. |
Use Scenario: Level-shifting between 5 V TTL logic and older 5 V CMOS peripherals with marginal input thresholds. IC Role / Device Role / Timing Role: Active-high buffer with VIH = 2.0 V ensures reliable recognition of weak CMOS high signals. Use Value: Resolves marginal logic-level mismatches without adding pull-up resistors or level-shifters, reducing BOM count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS244CDWR | ALS-family: slower (10 ns max tPLH), lower IOL (24 mA), lower ICC (34 mA max). | Better suited for low-power, noise-sensitive systems where speed is secondary to current consumption. | Select when replacing legacy ALS designs or optimizing for static power in battery-backed subsystems. |
| SN74HC244N | CMOS: 2 V–6 V supply, 7.5 mA IOL, 16 ns tPLH, higher noise immunity, no DC input loading. | Requires level translation if interfacing with pure TTL; unsuitable for direct 50 Ω line driving. | Choose for mixed-voltage systems or new designs prioritizing wide supply range and ESD robustness over raw speed. |
Compared with SN74ALS244CDWR and SN74HC244N, the SN74AS244ADWR delivers superior speed and drive strength for demanding 5 V TTL bus applications but consumes more quiescent current and lacks wide-supply flexibility.
Availability
SN74AS244ADWR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy memory subsystems, and parallel peripheral interfaces requiring stable component supply across multi-year production cycles.
Supply support for SN74AS244ADWR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74AS244ADWR belongs to TI's legacy 74AS logic family, engineered for high-speed, high-drive 5 V TTL system interfacing - targeting applications where performance exceeds LS/ALS requirements but full ECL cost/complexity is unjustified.
FAQ
What is the maximum output sink current specification for SN74AS244ADWR?
The SN74AS244ADWR is rated for a maximum low-level output current (IOL) of 64 mA per channel under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C). This value is confirmed in the "recommended operating conditions" table on page 5 of the SDAS142C datasheet and enables direct drive of multiple TTL loads or 50 Ω terminated lines without external amplification. Exceeding this rating risks parametric shift or thermal degradation.
Is SN74AS244ADWR pin-compatible with SN74LS244N?
Yes, SN74AS244ADWR is functionally and pinout-compatible with SN74LS244N in the same SOIC-20 (DW) or PDIP-20 package variants. Both share identical pin assignments for inputs (A1–A4, A1–A4), outputs (Y1–Y4, Y1–Y4), enables (1OE, 2OE), VCC, and GND. However, SN74AS244ADWR offers faster propagation delay (6.2 ns vs. 15 ns) and higher output drive (64 mA vs. 24 mA), making it a performance upgrade without PCB changes.
Does SN74AS244ADWR support operation at 3.3 V supply voltage?
No, SN74AS244ADWR is not specified for 3.3 V operation. Its recommended supply range is strictly 4.5 V to 5.5 V, and absolute maximum VCC is 7 V. Operation below 4.5 V may result in undefined logic thresholds, reduced noise margin, or failure to meet timing specifications. For 3.3 V systems, consider SN74LVC244A or SN74ALVC244, which are explicitly characterized for 3.3 V operation.
What is the meaning of the "-DWR" suffix in SN74AS244ADWR?
The "-DWR" suffix in SN74AS244ADWR denotes a specific packaging configuration: SOIC-20 (DW) package supplied in large tape-and-reel format (2000 units per reel), with RoHS-compliant NIPDAU lead finish and moisture sensitivity level (MSL) 1 rating for unlimited floor life at ≤30°C/60% RH. This differs from "-DW" (same package, no reel) and "-N" (PDIP-20 tube format), and is optimized for high-volume SMT assembly.
How does the dual OE (1OE/2OE) structure benefit system design with SN74AS244ADWR?
The dual active-low output-enable inputs (1OE and 2OE) in SN74AS244ADWR allow independent control of two 4-bit buffer groups - for example, enabling upper/lower byte lanes separately on a 16-bit bus. This eliminates the need for additional logic gates or multiplexers to manage partial bus access, simplifies address decoding in memory-mapped I/O, and supports time-multiplexed data transfers without introducing skew between lanes.
SN74AS244ADWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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
SN74AS244ADWR FAQ
1.How can I place an order for SN74AS244ADWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS244ADWR 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 SN74AS244ADWR reliable?
The price and inventory of SN74AS244ADWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS244ADWR is usually 5 days.
3.What payment methods are accepted for SN74AS244ADWR?
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Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS244ADWR?
SN74AS244ADWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS244ADWR 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 SN74AS244ADWR?
For technical support, including SN74AS244ADWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS244ADWR requirements.
6.How does Aetrix verify that SN74AS244ADWR is sourced from the original manufacturer or authorized distributors?
All SN74AS244ADWR 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 SN74AS244ADWR meets industry standards.
7.What is the process for return or replacement of SN74AS244ADWR?
All SN74AS244ADWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS244ADWR, 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 SN74AS244ADWR part is unused and in its original packaging.
Return procedure for SN74AS244ADWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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