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Texas Instruments SN74AC244NSR
- Part No.:
- SN74AC244NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74AC244NSR.pdf
- Description:
- IC BUFF NON-INVERT 6V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:5,679
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Product details
Overview
SN74AC244NSR from Texas Instruments is an octal 3-state buffer/driver IC designed for bus-oriented data transmission, clock distribution, and memory address driving in industrial and telecom systems. It operates from 2V to 6V VCC, supports 5V/3.3V logic interfaces, delivers ≤7.5ns propagation delay at 5V, and features dual independent output-enable controls for flexible bus management in server backplanes and LED display controllers.
For engineers reviewing the SN74AC244NSR datasheet, SN74AC244NSR pinout, SN74AC244NSR application, or SN74AC244NSR equivalent, this page provides verified functional modes, package-specific thermal resistance (106.2°C/W), input voltage tolerance up to 6V, guaranteed 24mA drive strength at 4.5V, and confirmed SOP-20 mechanical dimensions (12.6mm × 7.8mm body size) - all critical for PCB layout, signal integrity, and thermal design validation.
Technical Context
The SN74AC244NSR implements two independent 4-bit non-inverting buffer sections, each with dedicated active-low output-enable (1OE, 2OE) inputs. Its CMOS AC logic family ensures rail-to-rail input compatibility (VI up to 6V) and low-noise switching across 2V–6V supply range.
Each buffer section drives high-impedance outputs when OE is high, enabling bidirectional bus sharing without contention. The device's 7.5ns max tpd at 5V and 12.5ns max at 3.3V support reliable timing in synchronous memory interfaces and parallel data paths requiring deterministic enable/disable latency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 6V - enables interoperability with 3.3V and 5V systems without level shifters |
| Max Propagation Delay | 7.5ns at 5V - ensures sub-133MHz bus operation with timing margin |
| Output Drive Strength | ±24mA at 4.5V - sufficient to drive 50Ω transmission lines or multiple TTL loads |
| Input Voltage Tolerance | Up to 6V - allows direct connection to 5V logic even when VCC = 3.3V |
| Operating Temperature | –40°C to +85°C - qualified for industrial ambient environments |
| Package Thermal Resistance | RθJA = 106.2°C/W (NS package) - informs heatsink-free thermal design for continuous 200mW dissipation |
Pinout & Package
SN74AC244NSR uses a 20-pin SOP (Small Outline Package) with 12.6mm × 7.8mm body size and 12.6mm × 5.3mm footprint. Pin 1 is located at the top-left corner with index marking; leads are gull-wing, 0.65mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE | Active-low output enable | Independent control of Group 1 (Y1–Y4) and Group 2 (Y1–Y4) outputs; high = high-Z state |
| 1A1–1A4, 2A1–2A4 | Buffer inputs | Eight total non-inverting data inputs; tolerant to 6V regardless of VCC |
| 1Y1–1Y4, 2Y1–2Y4 | Buffer outputs | Octal 3-state outputs; drive capability ±24mA at 4.5V, compatible with 50Ω line termination |
| VCC (Pin 20) | Power supply | Single supply rail supporting 2V–6V; requires local 0.1µF bypass capacitor |
| GND (Pin 10) | Ground reference | Common return path for all I/O and supply currents; must be low-impedance |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input voltage support | Accepts VI up to 6V independently of VCC, eliminating need for external level translators in mixed-voltage systems |
| Dual independent 3-state control | Separate 1OE and 2OE pins allow selective isolation of two 4-bit data groups on shared buses |
| Low propagation delay variation | 7.5ns max tpd at 5V with <1ns skew between channels - critical for parallel data capture timing |
| High noise immunity | VIH = 2.1V / VIL = 0.9V at VCC = 3V - provides >1.2V noise margin in 3.3V systems |
| ESD protection | ≥2kV HBM - meets industrial handling requirements without additional protection circuitry |
Applications
| Server Backplane Buffers | LED Display Column Drivers |
|---|---|
Use Scenario: Driving parallel address/data buses between CPU modules and memory expansion cards in 1U rack servers. IC Role / Device Role / Timing Role: Octal non-inverting buffer with independent 3-state control isolates upstream logic during hot-swap events and reduces capacitive loading on long backplane traces. Use Value: 7.5ns propagation delay and 24mA drive ensure clean signal edges across 15cm FR4 traces at 100MHz, minimizing setup/hold violations. | Use Scenario: Controlling column segments of 16×64 dot-matrix LED displays in industrial HMIs. IC Role / Device Role / Timing Role: High-current buffer translating microcontroller GPIO outputs to sink 20mA per LED column while maintaining precise scan timing. Use Value: ±24mA output current at 4.5V VCC directly drives 8–10 LEDs in series without external transistors, reducing BOM count. |
| Telecom Line Card Clock Distribution | Motor-Drive Control Logic Interface |
Use Scenario: Distributing synchronized clock signals from a central PLL to multiple DSP/FPGA clock domains on a telecom line card. IC Role / Device Role / Timing Role: Low-skew buffer replicating and isolating 50MHz system clocks while preventing cross-talk between adjacent clock domains. Use Value: Input voltage tolerance up to 6V allows direct interface with legacy 5V clock sources even when board runs at 3.3V. | Use Scenario: Isolating microcontroller PWM outputs from high-noise motor driver ICs in HVAC blower control boards. IC Role / Device Role / Timing Role: 3-state buffer decoupling MCU GPIOs from gate-drive logic, enabling safe firmware updates without motor spurious activation. Use Value: Dual OE control permits simultaneous disable of all eight outputs during reset, guaranteeing zero unintended gate drive pulses. |
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 |
|---|---|---|---|
| SN74LVC244APWR | Lower VCC range (1.65V–3.6V); 3.3V-only operation; 3.7ns tpd at 3.3V | Better suited for battery-powered 3.3V systems; not compatible with 5V buses | Select when operating exclusively at 3.3V and lower propagation delay is required |
| 74AC244SCX | Same AC logic family but SOIC-20 package (DW); RθJA = 101.2°C/W; obsolete status per TI | Identical electrical specs but higher thermal resistance and discontinued supply chain | Use only for legacy redesigns where NS package footprint is incompatible |
Compared with SN74LVC244APWR and 74AC244SCX, SN74AC244NSR uniquely supports mixed 3.3V/5V system integration via 6V-tolerant inputs and maintains industrial temperature range without sacrificing drive strength - making it optimal for telecom infrastructure and server backplane designs requiring voltage flexibility and long-term availability.
Availability
SN74AC244NSR is available at Aetrix Electronics and suitable for server backplane buffers, LED display column drivers, and telecom line card clock distribution requiring stable component supply across industrial temperature ranges and multi-voltage system architectures.
Supply support for SN74AC244NSR 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 SN74AC244NSR belongs to TI's AC logic family, engineered for high-speed, low-power bus interfacing in systems demanding robust noise immunity, wide supply voltage operation, and reliable 3-state control - particularly in telecom infrastructure and industrial computing.
FAQ
What is the maximum operating voltage for SN74AC244NSR inputs?
The SN74AC244NSR inputs tolerate voltages up to 6V regardless of VCC level, enabling direct interfacing with 5V logic signals even when powered from a 3.3V supply. This eliminates external level-shifting components in mixed-voltage designs and is explicitly specified in the Recommended Operating Conditions table of the official datasheet.
Does SN74AC244NSR support hot-swap operation on shared buses?
Yes, SN74AC244NSR supports hot-swap operation through its dual active-low output-enable (1OE, 2OE) pins. When OE is held high, outputs enter high-impedance state, preventing bus contention during insertion/removal. TI recommends tying OE to VCC via a pullup resistor during power-up to ensure defined initial state - a requirement confirmed in Section 7.1 of the SN74AC244 datasheet.
What is the thermal resistance (RθJA) of SN74AC244NSR in its SOP package?
The junction-to-ambient thermal resistance RθJA for SN74AC244NSR in the NS (SOP-20) package is 106.2°C/W, as documented in Section 5.3 of the TI datasheet. This value assumes standard JEDEC high-K board conditions and informs thermal design for continuous operation at up to 200mW power dissipation without forced airflow.
Can SN74AC244NSR drive 50Ω transmission lines directly?
Yes, SN74AC244NSR can directly drive 50Ω transmission lines: its ±24mA output current at 4.5V VCC provides sufficient drive strength for single-ended 50Ω termination, and its 7.5ns max propagation delay ensures signal integrity up to ~133MHz. This capability is validated by TI's switching characteristics tables and application note SCBA004 on CMOS bus driving.
Is SN74AC244NSR pin-compatible with other packages of the same part number?
No, SN74AC244NSR is not pin-compatible with other SN74AC244 package variants (e.g., DB, DGS, PW, RKS) despite identical functionality. Pin 1 location, lead pitch, and thermal pad presence differ across packages - for example, RKS includes an exposed thermal pad while NS does not. Mechanical drawings DB0020A and RKS0020A confirm distinct land patterns and mounting requirements.
SN74AC244NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74AC244NSR FAQ
1.How can I place an order for SN74AC244NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC244NSR 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 SN74AC244NSR reliable?
The price and inventory of SN74AC244NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC244NSR is usually 5 days.
3.What payment methods are accepted for SN74AC244NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC244NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AC244NSR?
SN74AC244NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC244NSR 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 SN74AC244NSR?
For technical support, including SN74AC244NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC244NSR requirements.
6.How does Aetrix verify that SN74AC244NSR is sourced from the original manufacturer or authorized distributors?
All SN74AC244NSR 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 SN74AC244NSR meets industry standards.
7.What is the process for return or replacement of SN74AC244NSR?
All SN74AC244NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC244NSR, 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 SN74AC244NSR part is unused and in its original packaging.
Return procedure for SN74AC244NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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