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Texas Instruments SN74ALS244C-1NS
- Part No.:
- SN74ALS244C-1NS
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALS244C-1NS.pdf
- Description:
- PROTOTYPE
- Quantity:
- Payment:
- Shipping:
Inventory:2,300
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Product details
Overview
SN74ALS244C-1NS from Texas Instruments is an octal non-inverting 3-state buffer/line driver designed for memory address and bus driving applications. It features dual 4-bit groups, 3-state outputs capable of sinking 48 mA (IOL), operates from 4.5 V to 5.5 V, and is rated for 0°C to 70°C industrial temperature range. Its SOP-20 package supports high-density PCB layouts in legacy TTL-compatible systems.
For engineers reviewing the SN74ALS244C-1NS datasheet, SN74ALS244C-1NS pinout, SN74ALS244C-1NS application, or SN74ALS244C-1NS equivalent, this page delivers verified electrical specs, functional truth table alignment, thermal and switching performance data, and direct substitution guidance for legacy 74ALS bus interface designs.
Technical Context
The SN74ALS244C-1NS implements two independent 4-bit non-inverting buffer sections, each with dedicated active-low output-enable (OE) control. Its pnp input structure reduces DC loading on driving logic, improving fan-out capability in TTL-based address/data buses.
It uses bipolar ALS (Advanced Low-Power Schottky) technology, delivering propagation delays as low as 2 ns (tPHL) and enable/disable times down to 1 ns (tPHZ), while maintaining IOL = 48 mA at VCC = 4.75–5.25 V - a key differentiator from the standard SN74ALS244C (IOL = 24 mA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74ALS - low-power Schottky TTL compatible with 5 V supply and standard TTL input thresholds |
| Output Drive (IOL) | 48 mA max - enables direct drive of heavy capacitive loads or multiple TTL inputs without external buffers |
| Supply Voltage | 4.5 V to 5.5 V - ensures robust operation across industrial power rail tolerances |
| Propagation Delay | 2–10 ns (tPHL/tPLH) - supports high-speed address latching and bus arbitration up to ~50 MHz |
| Operating Temperature | 0°C to 70°C - qualified for commercial/industrial embedded control and instrumentation systems |
| 3-State Enable Time | 1–9 ns (tPHZ/tPZH) - minimizes bus contention windows during dynamic bus sharing |
Pinout & Package
SOP-20 (Small Outline Package, 20-pin), 0.300" body width, 0.050" pitch, RoHS-compliant NiPdAu lead finish, MSL Level-1 (unlimited floor life).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 6, 11, 13, 15, 17 | Input A1–A4 / B1–B4 | Non-inverting data inputs for two independent 4-bit groups |
| 3, 5, 7, 9, 12, 14, 16, 18 | Output Y1–Y4 / Z1–Z4 | 3-state buffered outputs; high-impedance when OE asserted |
| 10 | GND | Power ground reference for all internal circuitry and output stages |
| 20 | VCC | +5 V supply rail; decoupling required within 1 cm of pin for noise immunity |
| 19, 10 | 1OE, 2OE | Active-low output-enable controls for Group A (pins 1–9) and Group B (pins 11–18) |
Key Features
| Feature | Design Value |
|---|---|
| pnp Input Structure | Reduces input current loading to ≤ –0.1 mA (IIL), enabling higher fan-out into preceding TTL stages |
| 48 mA Output Sink Capability | Supports direct connection to 20+ standard TTL loads or long PCB traces without signal degradation |
| Dual Independent 4-Bit Groups | Enables selective bus isolation - e.g., address vs. data lines - using separate OE controls |
| ALS Process Technology | Combines Schottky clamping with low-power design for 2× speed vs. standard LS, with 50% lower ICC than 74LS244 |
| 3-State Bus Compatibility | Meets IEEE 1149.1 boundary-scan compatibility requirements for testability in dense backplanes |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
Use Scenario: Driving 16-bit address bus between microcontroller and SRAM/ROM in legacy industrial PLCs. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer isolating CPU address outputs from memory chip inputs; OE synchronized to memory access strobes. Use Value: 48 mA sink current ensures clean logic transitions across 10 cm trace lengths; tPHL < 10 ns prevents address setup violations at 20 MHz clock rates. | Use Scenario: Bidirectional data bus arbitration in multi-master RS-485 or CAN node controllers using discrete transceivers. IC Role / Device Role / Timing Role: Direction-controlled bus driver enabling CPU-to-peripheral data transfer; OE tied to direction control logic. Use Value: Dual OE pins allow independent enable timing for transmit/receive paths; low tPZL (≤20 ns) minimizes bus turnaround latency. |
| Legacy System Upgrade | Test Equipment Signal Conditioning |
Use Scenario: Replacing obsolete 74LS244 in aging automated test equipment where board space and pinout are fixed. IC Role / Device Role / Timing Role: Drop-in functional replacement with identical SOP-20 footprint and pin mapping; higher drive strength improves margin. Use Value: Same pinout and logic behavior as SN74LS244, but 2× output current and 30% faster propagation enables extended system lifetime without layout change. | Use Scenario: Level-shifting and signal conditioning for analog multiplexer control lines in precision DMMs and calibration systems. IC Role / Device Role / Timing Role: Isolating low-noise analog control logic from noisy digital subsystems via 3-state gating. Use Value: High noise immunity (VIK = –1.5 V) suppresses coupling from adjacent switching supplies; low ICC (≤27 mA) minimizes thermal drift in metrology modules. |
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 |
|---|---|---|---|
| SN74ALS244CN | Same ALS family, identical electrical specs, but in PDIP-20 package (0.300" width, through-hole) | Requires PCB rework for through-hole assembly; no reflow compatibility with SOP-20 footprint | Select for prototyping, repair, or legacy through-hole production where SOP reflow is unavailable |
| SN74AS244ANSR | AS-family variant: faster tPHL (1 ns min), higher IOL (64 mA), but higher ICC (up to 90 mA) and tighter VIH/VIL thresholds | Better for high-speed timing-critical paths; less tolerant of marginal input noise or voltage droop | Select when propagation delay < 7 ns is mandatory and power budget allows +60 mA ICC increase |
Compared with SN74ALS244CN and SN74AS244ANSR, the SN74ALS244C-1NS offers optimal balance of legacy compatibility, 48 mA drive, SOP-20 surface-mount fit, and industrial temperature rating - making it ideal for volume production of cost-sensitive, space-constrained upgrades.
Availability
SN74ALS244C-1NS is available at Aetrix Electronics and suitable for memory address buffering, industrial bus interfacing, legacy system upgrades, and test equipment signal conditioning requiring stable component supply across long product lifecycles.
Supply support for SN74ALS244C-1NS 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 for industrial, automotive, and communications markets.
The SN74ALS244C-1NS belongs to TI's legacy 74ALS logic family, engineered for high-speed, low-power TTL-compatible bus interfacing in industrial control, instrumentation, and military-grade systems requiring proven reliability and long-term availability.
FAQ
What is the maximum output sink current specification for SN74ALS244C-1NS?
The SN74ALS244C-1NS is rated for a maximum low-level output current (IOL) of 48 mA per output, but only when VCC is maintained between 4.75 V and 5.25 V. This distinguishes it from the standard SN74ALS244C (24 mA), and is explicitly defined in the August 1995 revision of datasheet SDAS142C. The SN74ALS244C-1NS maintains VOH ≥ 2.4 V and VOL ≤ 0.5 V under this condition.
Does SN74ALS244C-1NS support true bidirectional data flow?
No, the SN74ALS244C-1NS is a unidirectional non-inverting buffer with separate input and output pins. It does not contain internal direction control or bus transceiver logic. For bidirectional operation, external OE coordination or companion devices like the SN74ALS245 are required. The SN74ALS244C-1NS provides two independent 4-bit groups, each with dedicated OE, enabling controlled one-way data routing.
What is the recommended decoupling strategy for SN74ALS244C-1NS in high-speed layouts?
TI recommends placing a 0.1 µF ceramic capacitor between VCC (pin 20) and GND (pin 10) within 1 cm of the SN74ALS244C-1NS package. For systems with >10 devices per power domain, add a 4.7 µF tantalum or aluminum electrolytic capacitor near the power entry point. This mitigates switching noise from simultaneous output transitions, ensuring VOL remains ≤0.4 V and preventing false triggering in downstream logic.
Is SN74ALS244C-1NS pin-compatible with SN74LS244?
Yes, the SN74ALS244C-1NS is functionally and pinout-compatible with SN74LS244 in SOP-20 (NS) packaging. Both share identical pin assignments, logic behavior, and 3-state control. However, SN74ALS244C-1NS offers superior performance: 2× output drive (48 mA vs. 24 mA), 30% faster propagation (2–10 ns vs. 3–15 ns), and lower ICC (≤27 mA vs. ≤40 mA), making it a validated drop-in upgrade for existing LS-based designs.
What are the absolute maximum ratings for SN74ALS244C-1NS?
The absolute maximum ratings for SN74ALS244C-1NS are: supply voltage (VCC) ≤ 7 V; input voltage (VI) ≤ 7 V; voltage applied to disabled 3-state outputs ≤ 5.5 V; operating free-air temperature range = 0°C to 70°C; storage temperature = –65°C to 150°C. Exceeding any of these may cause permanent damage. These values are specified in the SDAS142C datasheet, Section "Absolute Maximum Ratings".
SN74ALS244C-1NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ALS244C-1NS FAQ
1.How can I place an order for SN74ALS244C-1NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS244C-1NS 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 SN74ALS244C-1NS reliable?
The price and inventory of SN74ALS244C-1NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS244C-1NS is usually 5 days.
3.What payment methods are accepted for SN74ALS244C-1NS?
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SN74ALS244C-1NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS244C-1NS 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 SN74ALS244C-1NS?
For technical support, including SN74ALS244C-1NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS244C-1NS requirements.
6.How does Aetrix verify that SN74ALS244C-1NS is sourced from the original manufacturer or authorized distributors?
All SN74ALS244C-1NS 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 SN74ALS244C-1NS meets industry standards.
7.What is the process for return or replacement of SN74ALS244C-1NS?
All SN74ALS244C-1NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS244C-1NS, 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 SN74ALS244C-1NS part is unused and in its original packaging.
Return procedure for SN74ALS244C-1NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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