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Texas Instruments SN74AHC244N
- Part No.:
- SN74AHC244N
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AHC244N.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,034
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Product details
Overview
SN74AHC244N from Texas Instruments is an octal noninverting 3-state buffer/driver IC used for bus interfacing, memory address driving, and clock distribution in digital systems. It operates from 2V to 5.5V, supports ±8mA output drive at 5V, features dual independent 4-bit banks with separate 3-state enables (1OE, 2OE), and delivers propagation delays as low as 3.9ns (tPLH/tPHL) at VCC = 5V with 15pF load - enabling reliable signal integrity in PC, network switch, and industrial control backplanes.
For engineers reviewing the SN74AHC244N datasheet, SN74AHC244N pinout, SN74AHC244N application, or SN74AHC244N equivalent, key selection criteria include its dual-bank 3-state architecture, rail-to-rail input tolerance up to 5.5V, balanced CMOS push-pull outputs, high-impedance state leakage ≤±2.5µA, and compatibility with 20-pin PDIP packaging for through-hole prototyping and legacy board replacement.
Technical Context
The SN74AHC244N implements two independent 4-bit noninverting buffer banks, each controlled by a dedicated output-enable input (1OE, 2OE). When asserted low, each bank drives its four outputs (e.g., 1Y1–1Y4) with full CMOS logic levels; when high, all outputs enter high-impedance state with leakage ≤±2.5µA.
Its inputs are overvoltage tolerant up to 5.5V regardless of VCC (2V–5.5V), enabling level translation between mixed-voltage domains. The device uses standard CMOS inputs with ≤10pF input capacitance and requires fast edge rates (≤20ns/V at 5V) to prevent oscillation or excessive power draw.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 5.5V - supports single-supply operation across 3.3V and 5V logic families without level shifters. |
| IOL / IOH | ±8mA at VCC = 5V - sufficient to drive 50Ω transmission lines or multiple CMOS loads without external buffers. |
| tPLH / tPHL | 3.9ns max at VCC = 5V, CL = 15pF - enables high-speed bus timing in PCs and network switches with tight skew budgets. |
| IOZ (High-Z Leakage) | ±2.5µA at VCC = 5.5V - ensures minimal bus contention and stable floating-bus behavior during disable. |
| VIH / VIL | 3.85V / 1.65V at VCC = 5.5V - provides 0.65V noise margin for robust TTL/CMOS-compatible signaling. |
| Input Capacitance (Ci) | 10pF max - limits loading on upstream drivers and preserves signal rise/fall times in dense routing. |
| ESD Rating (HBM) | ±2000V - meets industrial handling requirements without additional protection circuitry. |
Pinout & Package
SN74AHC244N is supplied in a 20-pin Plastic Dual In-line Package (PDIP) with 2.54mm pitch, 25.40mm × 6.35mm body size, and through-hole mounting. Pin 1 is marked with a notch or dot; pin numbering proceeds counterclockwise from top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low enable inputs controlling Bank 1 (pins 2,4,6,8 → 18,16,14,12) and Bank 2 (pins 11,13,15,17 → 9,7,5,3). |
| 2,4,6,8 | 1A1–1A4 | Bank 1 input signals - routed directly to corresponding outputs when 1OE = L. |
| 11,13,15,17 | 2A1–2A4 | Bank 2 input signals - routed directly to corresponding outputs when 2OE = L. |
| 18,16,14,12 | 1Y1–1Y4 | Bank 1 noninverting buffered outputs - high-impedance when 1OE = H. |
| 9,7,5,3 | 2Y1–2Y4 | Bank 2 noninverting buffered outputs - high-impedance when 2OE = H. |
| 10 | GND | Ground reference for all logic and output stages - must be low-impedance connection to minimize ground bounce. |
| 20 | VCC | Power supply input - requires local 0.1µF ceramic bypass capacitor placed adjacent to pin per layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input tolerance | Accepts VI up to 5.5V independent of VCC (2V–5.5V), enabling seamless 5V→3.3V down-translation in mixed-voltage systems. |
| Dual independent 3-state banks | Separate 1OE/2OE controls allow selective bus isolation - critical for multi-master arbitration and hot-swap I/O expansion. |
| Balanced CMOS output drive | Sources/sinks ±8mA symmetrically at 5V, ensuring matched rise/fall times and reduced EMI in high-speed trace routing. |
| Low dynamic power consumption | ICC ≤40µA at VCC = 5.5V - minimizes quiescent current in battery-backed or always-on control subsystems. |
| Fast propagation delay | 3.9ns typical tPLH/tPHL at 5V/15pF - supports >100MHz bus clocking with margin for setup/hold timing closure. |
Applications
| PC & Notebook Backplane Interface | Industrial Network Switch Data Path |
|---|---|
Use Scenario: Driving address/data buses between CPU and peripheral controllers on legacy ATX motherboards or embedded x86 designs. IC Role / Device Role / Timing Role: Noninverting 3-state buffer isolating memory-mapped I/O regions and enabling bidirectional bus sharing between multiple masters. Use Value: 5V-tolerant inputs interface directly with legacy ISA/PCI peripherals; ±8mA drive sustains signal integrity across 12cm PCB traces without termination resistors. |
Use Scenario: Buffering control signals between switch fabric ASICs and PHY transceivers in managed Ethernet switches. IC Role / Device Role / Timing Role: Dual-bank driver synchronizing configuration register writes and status reads across isolated voltage domains (3.3V control, 5V PHY). Use Value: Independent OE pins allow staggered enable sequencing to avoid simultaneous switching noise; 3.9ns delay ensures sub-10ns timing budget compliance. |
| Wearable Health Sensor Hub | Test & Measurement Equipment I/O Expansion |
Use Scenario: Level-shifting and buffering sensor data streams (ECG, SpO₂) from analog front-ends to low-power microcontrollers in compact wearable modules. IC Role / Device Role / Timing Role: Voltage translator and bus driver enabling 5V sensor outputs to interface safely with 3.3V MCU GPIOs while maintaining signal fidelity. Use Value: Input overvoltage tolerance eliminates need for external clamping diodes; 2V minimum VCC allows operation from single-cell Li-ion (2.7–4.2V) with margin. |
Use Scenario: Expanding digital I/O channels on automated test equipment (ATE) racks where multiple instruments share a common control bus. IC Role / Device Role / Timing Role: High-impedance bus isolator preventing signal contention during instrument reconfiguration or firmware updates. Use Value: ±2.5µA high-Z leakage guarantees stable bus states during hot-swap events; PDIP package supports hand-soldered field-replaceable 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 |
|---|---|---|---|
| SN74AHCT244N | CMOS input thresholds tied to TTL levels (VIH = 2.0V min), not rail-proportional - requires ≥2V input swing for reliable high detection at 3.3V VCC. | Better suited for legacy 5V TTL systems; less ideal for mixed 3.3V/5V environments requiring precise threshold control. | Choose SN74AHCT244N only when interfacing with older TTL logic families where guaranteed 2.0V VIH is required. |
| 74LVC244APW | Lower VCC range (1.65V–3.6V), smaller TSSOP-20 package (6.5mm × 4.4mm), and higher speed (tPD = 2.9ns @ 3.3V) but no 5V input tolerance. | Optimized for space-constrained, low-voltage portable electronics - incompatible with 5V signal sources without external level shifting. | Select 74LVC244APW for new 3.3V-only designs prioritizing footprint and speed; avoid when 5V-tolerant inputs are mandatory. |
Compared with SN74AHCT244N and 74LVC244APW, SN74AHC244N uniquely combines 2V–5.5V operation, 5.5V input tolerance, and PDIP packaging - making it the only option supporting legacy 5V systems, modern mixed-voltage interfaces, and through-hole prototyping in one device.
Availability
SN74AHC244N is available at Aetrix Electronics and suitable for PC motherboard repair, industrial network switch refurbishment, and test equipment I/O expansion requiring stable component supply and long-term obsolescence management.
Supply support for SN74AHC244N 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 SN74AHC244N belongs to TI's advanced high-speed CMOS (AHC) logic family, designed for low-power, high-drive bus interfacing in mixed-voltage digital systems where reliability, timing precision, and legacy compatibility are critical.
FAQ
What is the maximum operating temperature for SN74AHC244N?
The SN74AHC244N is rated for operation from –40°C to +125°C ambient temperature. This extended industrial temperature range ensures reliable performance in demanding environments such as network infrastructure equipment, industrial PLCs, and automotive under-hood control modules where thermal stability is essential. The PDIP package's thermal resistance (RθJA = 54.9°C/W) supports this rating with standard PCB copper pour.
Does SN74AHC244N support 3.3V-only operation?
Yes, SN74AHC244N fully supports 3.3V-only operation: VCC can be set to 3.3V ± 0.3V, VIH is 2.1V min, VIL is 0.9V max, and output drive is ±4mA - meeting all requirements for 3.3V LVTTL and LVCMOS systems. Its 5.5V input tolerance also allows safe interfacing with 5V peripherals without external protection.
How should unused inputs be handled on SN74AHC244N?
All unused inputs on SN74AHC244N must be terminated to either VCC or GND - never left floating. Floating CMOS inputs cause excessive power consumption, oscillation, and potential device damage. A 10kΩ pull-up or pull-down resistor is recommended for unconnected 1OE/2OE or A-input pins to ensure defined logic states and stable operation.
Can SN74AHC244N drive a 50Ω transmission line directly?
Yes, SN74AHC244N can drive a 50Ω transmission line directly when VCC = 5V: its ±8mA output drive corresponds to ~625mV across 50Ω, sufficient for short-to-medium length traces (<12cm) with proper source termination. For longer lines or stricter signal integrity, add a series damping resistor (22–33Ω) near the output pin as recommended in TI's layout guidelines.
Is SN74AHC244N pin-compatible with other 74-series octal buffers?
SN74AHC244N shares the same 20-pin PDIP footprint and pinout as SN74LS244N, SN74ALS244N, and SN74F244N - enabling drop-in replacement in legacy designs. However, differences in drive strength, propagation delay, and input thresholds require validation of timing margins and voltage compatibility before substitution.
SN74AHC244N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- 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:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74AHC244N FAQ
1.How can I place an order for SN74AHC244N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC244N 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 SN74AHC244N reliable?
The price and inventory of SN74AHC244N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC244N is usually 5 days.
3.What payment methods are accepted for SN74AHC244N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC244N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHC244N?
SN74AHC244N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC244N 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 SN74AHC244N?
For technical support, including SN74AHC244N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC244N requirements.
6.How does Aetrix verify that SN74AHC244N is sourced from the original manufacturer or authorized distributors?
All SN74AHC244N 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 SN74AHC244N meets industry standards.
7.What is the process for return or replacement of SN74AHC244N?
All SN74AHC244N units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC244N, 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 SN74AHC244N part is unused and in its original packaging.
Return procedure for SN74AHC244N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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