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Texas Instruments SN74ALS1244AN
- Part No.:
- SN74ALS1244AN
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS1244AN.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,735
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Product details
Overview
SN74ALS1244AN from Texas Instruments is a noninverting octal 3-state buffer/driver IC designed for memory address and bus driving in TTL-compatible systems. It features dual 4-bit channels, independent 3-state enable controls (1OE, 2OE), 8 mA low-level output drive, 12 mA high-level sink capability, and operates at 4.5–5.5 V over 0°C to 70°C.
For engineers reviewing the SN74ALS1244AN datasheet, SN74ALS1244AN pinout, SN74ALS1244AN application, or SN74ALS1244AN equivalent, this device is selected for legacy TTL bus buffering where low-power ALS logic, pnp-input reduced dc loading, and dual-channel independent enable control are required.
Technical Context
This device implements two independent 4-bit noninverting buffer groups (1A1–1A4 → 1Y1–1Y4; 2A1–2A4 → 2Y1–2Y4), each with dedicated 3-state output enable (1OE, 2OE). Inputs use pnp transistor structures to minimize dc input current-typical IIL = −0.1 mA and IIH = 20 µA at VCC = 5.5 V.
Propagation delays range from 3 ns (tPLH/tPHL min) to 14 ns (tPHL max) at CL = 50 pF; 3-state enable/disable times (tPZH/tPLZ/tPZL) are specified up to 22 ns. Output voltage levels meet standard TTL thresholds: VOH ≥ 2.4 V (IOH = −12 mA), VOL ≤ 0.4 V (IOL = 8 mA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74ALS - low-power Schottky TTL with pnp inputs for reduced dc loading |
| Function | Octal noninverting 3-state buffer with dual independent enables (1OE/2OE) |
| VCC Range | 4.5 V to 5.5 V - compatible with standard 5 V TTL supply rails |
| IOL / IOH | 8 mA / −12 mA - sufficient to drive multiple TTL loads or short bus stubs |
| Propagation Delay | 3–14 ns (A→Y) - supports bus speeds up to ~35 MHz in point-to-point configurations |
| 3-State Enable Time | 2–22 ns (OE→Y) - ensures clean bus arbitration without output contention |
| Operating Temperature | 0°C to 70°C - commercial-grade rating for industrial and computing equipment |
Pinout & Package
SN74ALS1244AN uses a 20-pin plastic DIP (PDIP-N) package with 300-mil width and through-hole mounting. Pin spacing is 0.1 inch; body width is 0.3 inches.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Output Enable (Channel 1) | Active-low control for Y1–Y4 outputs; disables all four outputs when high |
| 2OE | Output Enable (Channel 2) | Active-low control for Y1–Y4 of second channel; independent of 1OE |
| 1A1–1A4 | Inputs (Channel 1) | Noninverting data inputs feeding outputs 1Y1–1Y4 |
| 2A1–2A4 | Inputs (Channel 2) | Noninverting data inputs feeding outputs 2Y1–2Y4 |
| 1Y1–1Y4 | Outputs (Channel 1) | 3-state buffered noninverted copies of 1A1–1A4 |
| 2Y1–2Y4 | Outputs (Channel 2) | 3-state buffered noninverted copies of 2A1–2A4 |
| VCC | Power Supply | +5 V supply connection (Pin 20); decoupling recommended near pin |
| GND | Ground | Reference return (Pin 10); critical for noise immunity and switching integrity |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 3-state enables | Allows selective activation of either 4-bit channel without affecting the other - essential for multi-master bus arbitration |
| pnp input structure | Reduces input current loading by >90% vs. standard TTL - lowers power supply demand and improves fanout stability |
| ALS logic family compatibility | Direct drop-in replacement for 74LS244 with lower ICC (11–20 mA disabled vs. LS's ~25 mA) and improved noise margin |
| TTL-output voltage compliance | VOH ≥ 2.4 V @ −12 mA and VOL ≤ 0.4 V @ 8 mA - ensures reliable interfacing with legacy 74xx, 74LSxx, and microprocessor buses |
| 20-pin PDIP package | Industry-standard through-hole footprint enabling repairability, prototyping, and compatibility with legacy PCB layouts |
Applications
| Memory Address Buffering | System Bus Driver |
|---|---|
|
Use Scenario: Driving 16-bit address lines from a microprocessor to multiple memory chips on a shared bus. IC Role / Device Role / Timing Role: Noninverting octal buffer providing isolation and drive strength while enabling/disabling subsets of address lines per memory bank. Use Value: Dual OE pins allow independent gating of upper/lower address bytes, reducing bus contention during memory decode transitions. |
Use Scenario: Interfacing an 8-bit microcontroller data bus to peripheral devices with varying timing requirements. IC Role / Device Role / Timing Role: Bidirectional-capable 3-state driver (used unidirectionally) that isolates peripherals during reset or idle states. Use Value: 14 ns max propagation delay and sub-22 ns enable timing support synchronous peripheral handshaking at up to 20 MHz clock rates. |
| Legacy Industrial Controller I/O | Test Equipment Signal Conditioning |
|
Use Scenario: Expanding GPIO count in programmable logic controllers using discrete TTL logic backplanes. IC Role / Device Role / Timing Role: Level-shifting and fanout buffer between MCU I/O and relay drivers or optocouplers. Use Value: pnp inputs draw only 0.1 mA max per line - reduces cumulative loading on aging microcontroller ports. |
Use Scenario: Conditioning digital stimulus signals in automated test equipment before routing to DUT interface connectors. IC Role / Device Role / Timing Role: Impedance-matched, low-skew buffer stage ensuring signal integrity across long ribbon cables. Use Value: Matched tPLH/tPHL (3–14 ns) and tight enable timing minimize skew between parallel signal paths in multi-channel testers. |
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 | Higher ICC (25 mA disabled), no pnp inputs - draws more input current (IIL ≈ −0.4 mA) | Same pinout and function but higher power and lower noise immunity; suitable only if ALS speed/power advantages are not required | Select SN74LS244N only for cost-sensitive legacy replacements where board-level power budget allows extra 10–15 mA per device |
| SN74HC244N | CMOS technology: wider VCC range (2–6 V), lower ICC (< 8 µA), but TTL-input thresholds not guaranteed below 4.5 V | Not TTL-compatible at VCC < 4.5 V; requires level translation when interfacing with 5 V TTL buses | Choose SN74HC244N only in mixed-voltage systems with proper input threshold validation or added interface circuitry |
Compared with SN74LS244N and SN74HC244N, the SN74ALS1244AN delivers optimal balance of TTL compatibility, low input loading, and moderate speed for legacy 5 V bus designs - especially where board-level current budget and noise margin are constrained.
Availability
SN74ALS1244AN is available at Aetrix Electronics and suitable for memory address buffering, system bus driving, industrial controller I/O expansion, and test equipment signal conditioning requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS1244AN 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, delivering analog, embedded processing, logic, and interface solutions across industrial, automotive, and communications markets.
The SN74ALS1244AN belongs to TI's legacy 74ALS logic family, engineered specifically for high-density, low-power memory address and bus driver applications in 5 V TTL systems.
FAQ
What is the operating temperature range for SN74ALS1244AN?
The SN74ALS1244AN is characterized for operation from 0°C to 70°C - the commercial temperature grade. This distinguishes it from the SN54ALS1244A military version (−55°C to 125°C). The SN74ALS1244AN datasheet specifies all electrical parameters within this range, including propagation delay, output drive, and enable timing.
Does SN74ALS1244AN support true bidirectional data flow?
No - the SN74ALS1244AN is a unidirectional noninverting buffer with fixed input (A) and output (Y) terminals. It does not contain internal direction control or bus transceiver logic. For bidirectional operation, designers must pair it with complementary devices like the SN74ALS1240A (inverting version) or use dedicated transceivers such as the SN74ALS245A.
Can SN74ALS1244AN be used with 3.3 V logic systems?
No - the SN74ALS1244AN requires a minimum VCC of 4.5 V and is not specified for 3.3 V operation. Its input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and output drive characteristics are optimized for 5 V TTL compatibility. Using it at 3.3 V risks undefined logic states and insufficient VOH/VOL margins.
What is the maximum capacitive load SN74ALS1244AN can drive reliably?
The SN74ALS1244AN switching characteristics are tested with CL = 50 pF, and its 14 ns max tPHL/tPLH assumes this load. While it may drive larger capacitances, performance degrades linearly: at 100 pF, propagation delay increases ~30–40%, and rise/fall times widen. For >50 pF loads, add series termination or reduce trace length to maintain timing integrity.
Is SN74ALS1244AN RoHS compliant?
Yes - the SN74ALS1244AN and SN74ALS1244ANE4 variants are Pb-Free (RoHS compliant), with CU NIPDAU lead finish and no exemptions required. TI's packaging documentation confirms full RoHS compliance for this PDIP-N package variant, making it suitable for modern environmental compliance requirements in industrial and computing equipment.
SN74ALS1244AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- 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:
- 15mA, 16mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74ALS1244AN FAQ
1.How can I place an order for SN74ALS1244AN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS1244AN 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 SN74ALS1244AN reliable?
The price and inventory of SN74ALS1244AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS1244AN is usually 5 days.
3.What payment methods are accepted for SN74ALS1244AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS1244AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS1244AN?
SN74ALS1244AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS1244AN 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 SN74ALS1244AN?
For technical support, including SN74ALS1244AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS1244AN requirements.
6.How does Aetrix verify that SN74ALS1244AN is sourced from the original manufacturer or authorized distributors?
All SN74ALS1244AN 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 SN74ALS1244AN meets industry standards.
7.What is the process for return or replacement of SN74ALS1244AN?
All SN74ALS1244AN units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS1244AN, 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 SN74ALS1244AN part is unused and in its original packaging.
Return procedure for SN74ALS1244AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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