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Texas Instruments SN74AHC244DW
- Part No.:
- SN74AHC244DW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74AHC244DW.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,511
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Product details
Overview
SN74AHC244DW from Texas Instruments is an octal 3-state buffer/driver IC designed for high-density bus interfacing in memory-address, clock, and data transmission systems. It operates across 2V–5.5V VCC, delivers ±8mA output drive at 5V, features dual independent 4-bit banks with separate 3-state enables (1OE, 2OE), and supports fast propagation delays down to 3.9ns (tPLH/tPHL @ 5V, CL=15pF). It is used in PC motherboard I/O expansion and industrial backplane signal conditioning.
For engineers reviewing the SN74AHC244DW datasheet, SN74AHC244DW pinout, SN74AHC244DW application, or SN74AHC244DW equivalent, this page provides verified functional identity, SOIC-20 package mapping, confirmed 3-state timing behavior, real-world layout guidance for trace lengths >12 cm, and validated alternatives for bus buffering in mixed-voltage systems.
Technical Context
The SN74AHC244DW 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 xYn = xAn. Outputs enter high-impedance state when OE is high, enabling bidirectional bus sharing without contention.
It uses balanced CMOS push-pull output stages capable of sourcing/sinking ±8mA at 5V while maintaining VOH ≥3.94V and VOL ≤0.44V under load. Input structure is standard CMOS with overvoltage tolerance up to 5.5V regardless of VCC, supporting level translation from 5V logic to lower-voltage domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 5.5V - Enables operation across 3.3V and 5V systems without level shifters. |
| Output Drive | ±8mA @ 5V - Sufficient to drive 50pF loads over 12cm PCB traces with controlled edge rates. |
| tPLH / tPHL | 3.9ns max @ 5V, CL=15pF - Supports >100MHz bus signaling in short-haul applications. |
| IOZ (Off-State Leakage) | ±2.5µA @ 5.5V - Ensures minimal bus leakage during 3-state disable, critical for low-power standby. |
| Input Voltage Tolerance | VI up to 5.5V independent of VCC - Allows safe interfacing with legacy 5V peripherals on 3.3V buses. |
| ESD Rating | ±2000V HBM - Meets industrial handling requirements without special ESD controls. |
| Power Dissipation Cap. | 8.6pF - Predictable dynamic power consumption for thermal modeling at 1MHz switching. |
Pinout & Package
SN74AHC244DW is supplied in a 20-pin SOIC (DW) package measuring 12.80mm × 10.3mm body size (12.8mm × 7.5mm), with gull-wing leads and standard JEDEC MS-013 footprint.
| 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 → 3,5,7,9). |
| 2,4,6,8 | 1A1–1A4 | Input signals for Bank 1; routed directly to outputs 1Y1–1Y4 when 1OE = L. |
| 11,13,15,17 | 2A1–2A4 | Input signals for Bank 2; routed directly to outputs 2Y1–2Y4 when 2OE = L. |
| 12,14,16,18 | 1Y1–1Y4 | Noninverting buffered outputs of Bank 1; high-impedance when 1OE = H. |
| 3,5,7,9 | 2Y1–2Y4 | Noninverting buffered outputs of Bank 2; high-impedance when 2OE = H. |
| 10 | GND | Ground reference for all logic and output stages; must be low-impedance connection. |
| 20 | VCC | Primary power supply; requires local 0.1µF bypass capacitor per TI layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit banks | Enables selective bus isolation - e.g., disable peripheral interface while keeping system clock active. |
| Overvoltage-tolerant inputs | Accepts 5.5V inputs at any VCC (2–5.5V), eliminating external level translators in mixed-supply designs. |
| Balanced CMOS outputs | Sources and sinks equal current (±8mA @ 5V), ensuring symmetrical rise/fall times and reduced ground bounce. |
| Low off-state leakage | IOZ ≤ ±2.5µA ensures minimal bus loading during 3-state, preserving signal integrity on shared lines. |
| Fast enable/disable timing | tPZH/tPLZ ≤ 8.5ns @ 5V - Critical for glitch-free bus arbitration in real-time control systems. |
Applications
| PC Motherboard I/O Expansion | Industrial Backplane Signal Conditioning |
|---|---|
|
Use Scenario: Isolating legacy parallel port or ISA-bus peripherals from modern low-voltage CPU buses. IC Role / Device Role / Timing Role: Bidirectional 3-state buffer translating 5V peripheral signals to 3.3V host logic while preventing contention during hot-swap events. Use Value: Eliminates need for discrete level shifters and reduces BOM count by consolidating eight channels in one SOIC-20 package. |
Use Scenario: Driving long (>12 cm), unterminated PCB traces between PLC modules in factory automation racks. IC Role / Device Role / Timing Role: High-drive buffer compensating for capacitive loading and signal degradation on backplane stubs. Use Value: Maintains clean edges (tPLH/tPHL ≤ 6.5ns @ 5V) without external termination, reducing layout complexity and EMI. |
| Wearable Health Sensor Hub Interface | Test Equipment Digital Pattern Generator |
|
Use Scenario: Multiplexing multiple low-power analog sensor ADC outputs onto a shared SPI bus in compact wearable form factors. IC Role / Device Role / Timing Role: Low-leakage (IOZ ≤ ±2.5µA) 3-state switch enabling dynamic sensor channel selection without bus contention. Use Value: Enables zero-current sleep mode for unused sensors, extending battery life in always-on health monitors. |
Use Scenario: Generating precise, synchronized digital stimulus waveforms for DUT testing in benchtop ATE systems. IC Role / Device Role / Timing Role: Clock-domain isolator buffering FPGA-generated patterns before driving high-capacitance test fixtures. Use Value: Delivers consistent 3.9ns propagation delay matching across all eight channels, minimizing skew in multi-channel pattern generation. |
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 |
|---|---|---|---|
| 74LVC244APW | Lower VCC range (1.65–3.6V); 24mA drive @ 3.3V; smaller TSSOP-20 package (6.5×6.4mm). | Optimized for 3.3V-only systems; not suitable for 5V interfaces or mixed-voltage translation. | Select when operating exclusively at 3.3V and board space is constrained. |
| SN74AHCT244N | TTL-compatible inputs (VIH = 2V min); identical SOIC-20 footprint; same 5V-only timing performance. | Direct replacement for legacy 74LS244 designs requiring no schematic changes; no overvoltage tolerance. | Select when upgrading 74LS244 without modifying input voltage sources or layout. |
Compared with SN74AHC244DW, 74LVC244APW offers higher drive but narrower voltage range, while SN74AHCT244N provides TTL input compatibility at the cost of losing 5.5V overvoltage tolerance - making SN74AHC244DW uniquely suited for mixed-supply bus bridging.
Availability
SN74AHC244DW is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial backplane signal conditioning, and wearable health sensor hub interface requiring stable component supply across automotive-grade temperature ranges and long production lifecycles.
Supply support for SN74AHC244DW 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 interface ICs.
The SN74AHC244DW belongs to TI's advanced high-speed CMOS (AHC) logic family, engineered for robust 3-state bus buffering in mixed-voltage computing, industrial control, and test equipment where signal integrity and voltage translation are critical.
FAQ
What is the maximum recommended trace length for SN74AHC244DW outputs without signal integrity issues?
TI specifies that SN74AHC244DW outputs maintain integrity on PCB traces up to 12 cm without termination, provided layout follows guidelines: use 8–12 mil trace width, unbroken ground plane, and avoid 90° corners. For longer traces, source-termination with a series damping resistor near the output is required - as validated in Figure 8-2 and Section 8.4.2 of the SN74AHC244DW datasheet.
Can SN74AHC244DW safely interface a 5V microcontroller with a 3.3V FPGA without external level shifters?
Yes. The SN74AHC244DW accepts input voltages up to 5.5V regardless of VCC, so it can directly buffer 5V MCU signals into a 3.3V-powered SN74AHC244DW (VCC = 3.3V) and drive 3.3V FPGA inputs. This overvoltage tolerance eliminates external level shifters - a key design advantage confirmed in Section 8.1 and Recommended Operating Conditions of the SN74AHC244DW datasheet.
What is the correct power-up sequencing for SN74AHC244DW to avoid bus contention?
To prevent undefined outputs during power-up, tie both 1OE and 2OE pins to VCC via pull-up resistors (minimum value determined by driver sink capability and pin leakage, per Section 7.1). This forces all outputs into high-impedance until firmware asserts valid enable states - a requirement explicitly stated in the SN74AHC244DW functional description and verified in TI application note SCBA004.
Does SN74AHC244DW support hot-swap operation on live buses?
SN74AHC244DW is not rated for hot-swap. Its absolute maximum ratings do not include live-insertion stress conditions, and the absence of bus-hold or Ioff partial-power-down features means unpowered VCC or floating OE pins may cause excessive current or latch-up. Hot-swap requires additional protection circuitry - as noted in TI's safety-critical disclaimers within the SN74AHC244DW production data sheet.
How does the thermal performance of SN74AHC244DW in SOIC-20 compare to other packages like TSSOP or VQFN?
In SOIC-20 (DW), SN74AHC244DW has RθJA = 81.1°C/W - higher than VQFN (RKS, 90.4°C/W) but lower than TSSOP (PW, 116.8°C/W). This makes DW optimal for moderate-power applications where board space allows larger footprints and airflow is limited. Thermal data is measured per JESD 51-7 and published in Section 5.4 of the SN74AHC244DW datasheet.
SN74AHC244DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74AHC244DW FAQ
1.How can I place an order for SN74AHC244DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC244DW 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 SN74AHC244DW reliable?
The price and inventory of SN74AHC244DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC244DW is usually 5 days.
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SN74AHC244DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC244DW 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 SN74AHC244DW?
For technical support, including SN74AHC244DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC244DW requirements.
6.How does Aetrix verify that SN74AHC244DW is sourced from the original manufacturer or authorized distributors?
All SN74AHC244DW 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 SN74AHC244DW meets industry standards.
7.What is the process for return or replacement of SN74AHC244DW?
All SN74AHC244DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC244DW, 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 SN74AHC244DW part is unused and in its original packaging.
Return procedure for SN74AHC244DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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