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Texas Instruments SN74AHC244NSR
- Part No.:
- SN74AHC244NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74AHC244NSR.pdf
- Description:
- IC BUFFER NON-INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,945
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Product details
Overview
SN74AHC244NSR from Texas Instruments is an octal 3-state buffer/driver IC designed for bus interface, memory address driving, and clock distribution in high-density digital systems. It operates across 2V–5.5V VCC, delivers ±8 mA output drive at 5V, supports 10 ns typical propagation delay (tPLH/tPHL) under 50 pF load, and features dual independent 4-bit banks with separate 3-state enable controls - used in PC motherboard I/O expansion and industrial backplane data routing.
For engineers reviewing the SN74AHC244NSR datasheet, SN74AHC244NSR pinout, SN74AHC244NSR application, or SN74AHC244NSR equivalent, key selection criteria include its 20-pin SOP (NS) package, rail-to-rail CMOS input tolerance up to 5.5V, balanced push-pull 3-state outputs, and compatibility with mixed-voltage logic translation in embedded control and test equipment interfaces.
Technical Context
The SN74AHC244NSR implements two independent 4-bit noninverting buffer banks, each controlled by a dedicated output-enable input (1OE, 2OE). Each bank drives four outputs (e.g., 1Y1–1Y4) from corresponding inputs (1A1–1A4), with boolean function Yn = An. Outputs enter high-impedance state when OE is high, enabling bidirectional bus sharing without external direction control.
It uses advanced AHC CMOS process technology to achieve low power consumption (ICC ≤ 40 µA at 5.5V), fast switching (tPLH/tPHL ≤ 8.5 ns at VCC = 5V, CL = 50 pF), and robust noise immunity (VIL(D) = 1.5V, VIH(D) = 3.5V at 5V). Input transition rate is specified at 20 ns/V for 5V operation, ensuring stable timing under fast-edge conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 5.5V - supports single-supply operation across 3.3V and 5V logic domains, enabling voltage-level translation without level shifters. |
| Output Drive | ±8 mA at VCC = 5V - sufficient to drive 50 pF loads over 12 cm PCB traces while maintaining signal integrity in backplane applications. |
| Propagation Delay | ≤ 8.5 ns (tPLH/tPHL, VCC = 5V, CL = 50 pF) - enables reliable operation in 100+ MHz bus timing windows with margin. |
| 3-State Enable Time | tPZH/tPHZ ≤ 8.5 ns (VCC = 5V, CL = 50 pF) - ensures rapid bus arbitration and minimal contention window during multi-driver arbitration. |
| Input Voltage Tolerance | VI up to 5.5V regardless of VCC - allows interfacing with higher-voltage peripherals (e.g., legacy 5V sensors) while powered from 3.3V rails. |
| ESD Rating | ±2000 V HBM - meets industrial-grade handling requirements without additional protection circuitry on board. |
| Operating Temperature | –40°C to +125°C - qualified for extended temperature operation in automotive body control modules and industrial PLC I/O cards. |
Pinout & Package
The SN74AHC244NSR is supplied in a 20-pin SOP (Small Outline Package) with body dimensions 12.60 mm × 5.30 mm and overall package size 12.60 mm × 7.8 mm. Pin 1 is marked with a notch or dot; pin numbering follows standard counter-clockwise convention from top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low 3-state enable inputs - each controls four outputs in its respective bank; tie high via pull-up to ensure high-Z during power-up. |
| 2, 4, 6, 8 11, 13, 15, 17 |
1A1–1A4, 2A1–2A4 | Buffer input terminals - accept CMOS logic levels; must be terminated to VCC or GND if unused to prevent floating inputs. |
| 3, 5, 7, 9 12, 14, 16, 18 |
2Y4–2Y1, 1Y4–1Y1 | Noninverting buffered outputs - provide rail-to-rail swing and ±8 mA drive; high-impedance when corresponding OE is high. |
| 10 | GND | Ground reference - connects to system ground plane; multiple vias recommended for thermal and noise performance. |
| 20 | VCC | Power supply - requires local 0.1 µF ceramic bypass capacitor placed within 3 mm of pin for stable high-speed operation. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input voltage tolerance | Inputs accept up to 5.5V regardless of VCC - enables seamless down-translation from 5V peripherals to 3.3V microcontrollers without external level shifters. |
| Balanced CMOS 3-state outputs | Sinks and sources equal current (±8 mA at 5V) - eliminates bus contention risk and ensures symmetrical rise/fall times on shared data lines. |
| Dual independent 4-bit banks | Separate 1OE/2OE controls allow selective enabling of two logical groups - simplifies address/data bus segmentation in FPGA or ASIC interface designs. |
| Low dynamic power consumption | Cpd = 8.6 pF at 5V - minimizes switching current and heat generation in high-frequency clock distribution and burst-mode I/O applications. |
| Fast enable/disable timing | tPZH/tPHZ ≤ 8.5 ns at 5V - reduces bus turnaround latency in time-critical protocols like SPI daisy-chain or JTAG boundary scan. |
Applications
| PC Motherboard I/O Expansion | Industrial Backplane Data Routing |
|---|---|
|
Use Scenario: Driving parallel GPIO, SMBus, or LPC signals between chipset and peripheral controllers on ATX motherboards. IC Role / Device Role / Timing Role: Noninverting 3-state buffer providing isolation and fanout enhancement for 3.3V control buses with hot-swap capability. Use Value: Enables clean signal integrity over 10+ cm traces using series damping resistors, while supporting mixed-voltage signaling without level-shifting components. |
Use Scenario: Interfacing modular I/O cards to central controller in programmable logic controller (PLC) chassis with standardized backplane connectors. IC Role / Device Role / Timing Role: Bus driver managing bi-directional data flow between slot-based modules and main CPU, with per-slot enable control. Use Value: Dual-bank architecture allows independent enable/disable of analog input and digital output modules, reducing cross-talk and improving fault isolation. |
| Automotive Body Control Module | Test & Measurement Equipment |
|
Use Scenario: Buffering sensor interface signals (e.g., LIN transceiver status, door lock actuator commands) in vehicle body domain ECUs. IC Role / Device Role / Timing Role: High-immunity buffer isolating noisy 12V subsystems from low-voltage MCU logic, operating across –40°C to +125°C ambient. Use Value: ±2000 V HBM ESD rating and wide VCC range eliminate need for external TVS diodes in cost-sensitive automotive modules. |
Use Scenario: Signal conditioning and fanout for pattern generators, logic analyzers, and automated test fixtures requiring precise timing and low skew. IC Role / Device Role / Timing Role: Clock and data line repeater ensuring sub-10 ns propagation delay matching across 8-channel parallel stimulus paths. Use Value: Tight tsk(o) ≤ 1 ns (CL = 50 pF) guarantees channel-to-channel skew control critical for synchronized multi-pin testing. |
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); 24 mA drive at 3.3V; faster tPLH (5.2 ns typical) | Optimized for 3.3V-only systems; not suitable for 5V-tolerant interfaces or mixed-voltage translation | Select when operating exclusively at 3.3V with higher drive demand and no 5V input requirement. |
| 74AHC244D,653 (Nexperia) | Identical AHC family specs; same 2V–5.5V range and ±8 mA drive; SO20 package (same footprint as NS) | Drop-in replacement with identical pinout and timing; qualified to AEC-Q200 for automotive use | Choose for automotive qualification or dual-sourcing where TI part availability is constrained. |
Compared with SN74AHC244NSR, SN74LVC244APWR offers higher drive and speed but sacrifices 5V input tolerance and mixed-voltage flexibility, while 74AHC244D,653 provides identical electrical behavior with added automotive qualification - making it ideal for safety-critical or supply-diversified designs.
Availability
SN74AHC244NSR is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial backplane data routing, and automotive body control module applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for SN74AHC244NSR 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, with over 50 years of innovation in high-reliability digital interface ICs.
The SN74AHC244NSR belongs to TI's AHC logic family, engineered for high-speed, low-power 3-state bus interfacing in mixed-voltage systems - targeting industrial automation, computing infrastructure, and automotive electronics.
FAQ
What is the maximum output current per pin for SN74AHC244NSR?
The SN74AHC244NSR supports ±8 mA DC output current per pin at VCC = 5V, as specified in the Recommended Operating Conditions table. This value ensures reliable drive into standard 50 pF loads while staying within absolute maximum ratings of ±25 mA per output. Exceeding this limit risks thermal overstress or timing degradation.
Does SN74AHC244NSR support 5V-tolerant inputs when powered from 3.3V?
Yes, SN74AHC244NSR accepts input voltages up to 5.5V regardless of VCC level - confirmed in Section 5.3 Recommended Operating Conditions. When powered from 3.3V, it safely interfaces with 5V logic signals, enabling down-translation without external level shifters in mixed-voltage systems.
What is the correct power-up sequence to avoid bus contention with SN74AHC244NSR?
To prevent undefined outputs during power-up, tie both 1OE and 2OE pins to VCC through 10 kΩ pull-up resistors. This forces all outputs into high-impedance state until firmware asserts valid enable signals - a requirement explicitly stated in Section 7.1 Overview of the datasheet.
Can SN74AHC244NSR drive a 50 Ω transmission line directly?
No - SN74AHC244NSR is not designed for direct 50 Ω termination. Its output structure targets capacitive loads (e.g., 50 pF), not resistive transmission lines. For >12 cm traces, TI recommends source-series damping (e.g., 22–33 Ω resistor near output) as shown in Figure 8-7 to suppress ringing and maintain signal integrity.
Is SN74AHC244NSR pin-compatible with other 20-pin octal buffers like SN74LS244?
No - SN74AHC244NSR has identical pinout to SN74AHC244 variants (e.g., DW, DGV) but differs electrically and physically from bipolar LS-family parts. While pin numbers match for inputs/outputs/GND/VCC, LS devices require different biasing, have higher drive strength asymmetry, and lack 5V-tolerant inputs - making them non-interchangeable without design validation.
SN74AHC244NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74AHC244NSR FAQ
1.How can I place an order for SN74AHC244NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC244NSR 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 SN74AHC244NSR reliable?
The price and inventory of SN74AHC244NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC244NSR is usually 5 days.
3.What payment methods are accepted for SN74AHC244NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC244NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHC244NSR?
SN74AHC244NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC244NSR 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 SN74AHC244NSR?
For technical support, including SN74AHC244NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC244NSR requirements.
6.How does Aetrix verify that SN74AHC244NSR is sourced from the original manufacturer or authorized distributors?
All SN74AHC244NSR 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 SN74AHC244NSR meets industry standards.
7.What is the process for return or replacement of SN74AHC244NSR?
All SN74AHC244NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC244NSR, 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 SN74AHC244NSR part is unused and in its original packaging.
Return procedure for SN74AHC244NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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