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Texas Instruments SN74ALS1244ADWR
- Part No.:
- SN74ALS1244ADWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS1244ADWR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,654
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Product details
Overview
SN74ALS1244ADWR from Texas Instruments is an octal noninverting 3-state buffer/driver IC designed for memory address and bus driving applications. It features dual 4-bit channels, 20-pin SOIC (DW) package, 5 V nominal supply, ±12 mA output drive, and propagation delays as low as 3 ns. It operates from 0°C to 70°C and supports high-density bus interfacing in legacy TTL-compatible systems.
For engineers reviewing the SN74ALS1244ADWR datasheet, SN74ALS1244ADWR pinout, SN74ALS1244ADWR application, or SN74ALS1244ADWR equivalent, key selection criteria include 3-state bus contention control, ALS-family speed-power tradeoff, pnp-input DC loading reduction, and compatibility with 5-V TTL logic families in memory and clock distribution circuits.
Technical Context
This device implements two independent 4-bit noninverting buffer sections, each controlled by a dedicated output-enable input (1OE, 2OE). Each section drives four outputs (1Y1–1Y4 or 2Y1–2Y4) from four inputs (1A1–1A4 or 2A1–2A4), enabling bidirectional bus isolation without inversion.
Its ALS (Advanced Low-Power Schottky) architecture delivers faster switching than standard LS TTL while maintaining compatible voltage thresholds (VIH = 2 V, VIL = 0.8 V) and output drive strength (IOL = 16 mA, IOH = −12 mA). The pnp input structure reduces input current loading, improving fanout in dense address-bus configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.5 V to 5.5 V - Ensures robust operation across industrial 5 V rail tolerances. |
| High-Level Input Voltage (VIH) | 2.0 V min - Compatible with standard TTL and ALS logic families' output high levels. |
| Low-Level Input Voltage (VIL) | 0.8 V max - Accepts standard TTL low-level signals without misinterpretation. |
| Output Drive (IOL / IOH) | 16 mA sink / −12 mA source - Sufficient to drive multiple TTL loads or terminated transmission lines. |
| Propagation Delay (tPLH/tPHL) | 3–14 ns - Enables reliable operation in sub-20 ns address-bus timing windows. |
| 3-State Enable/Disable Time | tPZH = 2–13 ns, tPZL = 6–22 ns - Supports fast bus arbitration and dynamic channel switching. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial-grade embedded and computing equipment. |
Pinout & Package
SN74ALS1244ADWR is housed in a 20-pin SOIC (DW) package measuring 7.5 mm × 12.8 mm with 0.65 mm lead pitch. The package is RoHS-compliant, green (no Sb/Br), and moisture-sensitive level 1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Output enable (active-low) for Channel 1 | Controls Y1–Y4 outputs; low enables, high places them in high-impedance state. |
| 1A1–1A4 | Inputs for Channel 1 | Noninverting data inputs driving corresponding Y1–Y4 outputs when 1OE is active. |
| 1Y1–1Y4 | Outputs for Channel 1 | Buffered, 3-state noninverting outputs; electrically isolated when 1OE is high. |
| 2OE | Output enable (active-low) for Channel 2 | Independent control of Y1–Y4 outputs on second channel; enables dual-bank bus management. |
| 2A1–2A4 | Inputs for Channel 2 | Separate input set for second 4-bit buffer group, supporting parallel or staggered addressing. |
| 2Y1–2Y4 | Outputs for Channel 2 | Dual-channel output capability allows interleaved or mirrored bus driving without external logic. |
| VCC (Pin 20) | Positive supply | 5 V power rail connection; decoupling capacitor placement near this pin is critical for noise immunity. |
| GND (Pin 10) | Ground reference | Common return path for all I/O and internal circuitry; must be low-impedance for stable 3-state transitions. |
Key Features
| Feature | Design Value |
|---|---|
| Octal noninverting 3-state buffering | Two independent 4-bit channels support flexible memory address or data bus segmentation. |
| pnp input structure | Reduces input current loading to ≤0.1 mA, increasing fanout and reducing driver-stage burden. |
| ALS logic family performance | Combines LS-speed (≤14 ns delay) with lower power consumption versus standard LS TTL. |
| Bus-oriented output architecture | Simultaneous high-impedance disable of all eight outputs prevents bus contention during arbitration. |
| SOIC (DW) packaging | Surface-mount 20-pin footprint enables high-density PCB layouts in space-constrained systems. |
Applications
| Memory Address Buffering | System Bus Isolation |
|---|---|
|
Use Scenario: Driving 16-bit address lines from a microprocessor to multiple memory banks in a 1980s–1990s embedded controller. IC Role / Device Role / Timing Role: Noninverting 3-state buffer isolating CPU address outputs from shared memory bus segments. Use Value: Prevents address-line contention during DMA cycles via synchronized OE control, ensuring deterministic bus access. |
Use Scenario: Interfacing a CPU data bus to peripheral controllers with different timing requirements in a multi-master system. IC Role / Device Role / Timing Role: Bidirectional bus driver enabling time-multiplexed data transfer between CPU and peripherals. Use Value: Dual-channel OE inputs allow independent enable/disable of each 4-bit segment, supporting partial bus updates without full-cycle stalls. |
| Legacy Clock Distribution | TTL-Compatible Signal Fanout |
|
Use Scenario: Distributing a system clock signal to multiple synchronous logic blocks requiring matched edge timing. IC Role / Device Role / Timing Role: Low-skew noninverting buffer replicating clock edges with minimal added jitter (≤14 ns max delay variation). Use Value: ALS-family propagation consistency ensures setup/hold timing margins are preserved across fanout branches. |
Use Scenario: Expanding TTL logic output fanout beyond standard 10-unit load limits in industrial control backplanes. IC Role / Device Role / Timing Role: High-current (16 mA sink) buffer stage restoring signal integrity after multiple gate loads. Use Value: Maintains VIH/VIL margins over long traces by sourcing/sinking sufficient current to overcome line capacitance and leakage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal noninverting 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS244N | Standard LS TTL; higher ICC (20 mA typical), slower tPLH (15–25 ns), no pnp inputs. | Higher power draw and longer propagation delay limit use in high-speed or thermally constrained designs. | Acceptable where legacy LS compatibility is mandatory and timing budget allows ≥20 ns delays. |
| SN74F244N | Fast TTL; faster tPLH (3–10 ns) but higher ICC (40 mA), greater noise sensitivity, no pnp input benefit. | Superior speed at cost of power and EMI margin; unsuitable for low-noise or low-power legacy upgrades. | Preferred only when sub-10 ns propagation is required and board-level noise filtering is implemented. |
Compared with SN74LS244N and SN74F244N, the SN74ALS1244ADWR delivers optimal balance of speed (3–14 ns), power (11–20 mA ICC), and input loading (≤0.1 mA II), making it the preferred choice for upgrading LS-based systems where thermal headroom and bus loading are constraints.
Availability
SN74ALS1244ADWR is available at Aetrix Electronics and suitable for memory address buffering, system bus isolation, and legacy TTL clock distribution requiring stable component supply and long-term obsolescence support.
Supply support for SN74ALS1244ADWR 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 SN74ALS1244ADWR belongs to TI's legacy ALS logic family, engineered for high-speed, low-power 5 V TTL-compatible interfacing in memory subsystems and bus architectures of 1980s–1990s computing platforms.
FAQ
What is the operating temperature range for SN74ALS1244ADWR?
The SN74ALS1244ADWR is characterized for operation from 0°C to 70°C, meeting commercial-grade environmental requirements. This range aligns with standard desktop computing and industrial control equipment specifications. The device does not support extended or military temperature ranges-those are covered by the SN54ALS1244A variant. Always verify ambient and junction temperature margins in your layout when using SN74ALS1244ADWR.
Does SN74ALS1244ADWR support true bidirectional data flow?
No, SN74ALS1244ADWR is a unidirectional noninverting buffer with separate input and output terminals per channel. It lacks internal direction-control logic or bus transceiver functionality. Data flows strictly from A-inputs to Y-outputs; bidirectional operation requires external control logic or a dedicated transceiver like the SN74ALS245. The dual OE inputs enable selective channel enablement but do not reverse signal direction.
What is the maximum capacitive load SN74ALS1244ADWR can drive reliably?
Per the datasheet switching characteristics, SN74ALS1244ADWR is specified with CL = 50 pF in timing tests. While it can drive heavier loads, exceeding 50 pF increases propagation delay and may degrade edge rate due to limited output drive (±12 mA/16 mA). For >50 pF loads, add series termination or reduce trace length. SN74ALS1244ADWR performance remains stable up to ~75 pF with marginal timing impact, but design validation is required.
Is SN74ALS1244ADWR pin-compatible with SN74ALS244 variants?
Yes, SN74ALS1244ADWR shares identical pinout and function mapping with other SN74ALS1244x variants (e.g., SN74ALS1244AN, SN74ALS1244ADW) and is functionally equivalent to SN74ALS244 in channel count and logic behavior-but SN74ALS244 is inverting. The SN74ALS1244ADWR is noninverting and matches the pinout of the SN74ALS1244 family. No PCB changes are needed when substituting within this family.
What does "NRND" status mean for SN74ALS1244ADWR?
"NRND" (Not Recommended for New Designs) indicates Texas Instruments no longer promotes SN74ALS1244ADWR for new projects, though it remains in production to support existing customers. Aetrix Electronics maintains inventory and offers lifecycle management-including last-time-buy planning and cross-reference guidance-to ensure continuity for legacy systems still relying on SN74ALS1244ADWR in deployed hardware.
SN74ALS1244ADWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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:
- 15mA, 16mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74ALS1244ADWR FAQ
1.How can I place an order for SN74ALS1244ADWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS1244ADWR 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 SN74ALS1244ADWR reliable?
The price and inventory of SN74ALS1244ADWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS1244ADWR is usually 5 days.
3.What payment methods are accepted for SN74ALS1244ADWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS1244ADWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS1244ADWR?
SN74ALS1244ADWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS1244ADWR 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 SN74ALS1244ADWR?
For technical support, including SN74ALS1244ADWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS1244ADWR requirements.
6.How does Aetrix verify that SN74ALS1244ADWR is sourced from the original manufacturer or authorized distributors?
All SN74ALS1244ADWR 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 SN74ALS1244ADWR meets industry standards.
7.What is the process for return or replacement of SN74ALS1244ADWR?
All SN74ALS1244ADWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS1244ADWR, 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 SN74ALS1244ADWR part is unused and in its original packaging.
Return procedure for SN74ALS1244ADWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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