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Texas Instruments SN74AHC244DBR
- Part No.:
- SN74AHC244DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74AHC244DBR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,670
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Product details
Overview
SN74AHC244DBR from Texas Instruments is an octal 3-state noninverting buffer/driver IC designed for bus-oriented memory address, clock, and data line driving in high-density digital systems. It operates from 2V to 5.5V, delivers ±8mA output drive at 5V, supports 10ns typical propagation delay (VCC = 5V, CL = 15pF), and features dual independent 4-bit banks with separate 3-state enable controls - used in PC motherboard I/O expansion and industrial backplane interfaces.
For engineers reviewing the SN74AHC244DBR datasheet, SN74AHC244DBR pinout, SN74AHC244DBR application, or SN74AHC244DBR equivalent, this page provides verified functional identity, SSOP-20 package mapping, confirmed 3-state timing parameters, real-world bus-driving use cases, and two validated alternative parts with documented electrical and application differences.
Technical Context
The SN74AHC244DBR 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. All outputs enter high-impedance state when their respective OE is high.
It uses balanced CMOS push-pull 3-state outputs capable of sourcing/sinking ±8mA at 5V, with input overvoltage tolerance up to 5.5V regardless of VCC. The device exhibits 1ns typical output skew (tsk(o)) at 50pF load and meets JESD17 latch-up immunity (>250mA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 5.5V - supports mixed-voltage system interfacing and 3.3V/5V legacy bus translation |
| IOL / IOH (5V) | ±8mA - sufficient to drive 50pF loads across 12cm PCB traces without signal integrity degradation |
| tPLH / tPHL (5V, 15pF) | 3.9ns to 6.5ns - enables >100MHz bus operation in low-skew applications |
| tsk(o) (50pF) | 1ns max - ensures simultaneous switching of all 4 outputs within a bank for clean bus transitions |
| Input Voltage Tolerance | VI up to 5.5V at any VCC - allows direct connection to 5V logic even when powered at 3.3V |
| ICC (5.5V) | 40µA max - ultra-low static power for always-on control-path buffering |
| ESD HBM | ±2000V - meets industrial handling requirements without additional protection circuitry |
Pinout & Package
SN74AHC244DBR is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch, 7.2mm × 7.8mm body outline, and 7.50mm × 5.30mm footprint - optimized for high-density PCB layouts while maintaining hand-solderability.
| 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) respectively |
| 2,4,6,8 | 1A1–1A4 | Input signals for Bank 1 - routed directly to corresponding Y outputs when 1OE = L |
| 11,13,15,17 | 2A1–2A4 | Input signals for Bank 2 - routed directly to corresponding Y outputs when 2OE = L |
| 18,16,14,12 | 1Y1–1Y4 | Noninverting buffered outputs of Bank 1 - high-impedance when 1OE = H |
| 9,7,5,3 | 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 | Power supply for internal logic and output drivers - requires local 0.1µF bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit banks | Enables selective bus isolation - e.g., disable peripheral address lines while keeping data lines active |
| Overvoltage-tolerant inputs | Accepts 5.5V inputs at any VCC (2–5.5V), eliminating level-shifters in mixed-supply systems |
| Balanced ±8mA drive (5V) | Drives standard TTL/CMOS loads and moderate PCB trace capacitance without external buffers |
| 1ns max output skew | Ensures deterministic timing across all 4 outputs in a bank - critical for synchronous bus protocols |
| JESD17 latch-up immunity >250mA | Withstands transient current faults in industrial environments without destructive failure |
Applications
| PC Motherboard I/O Expansion | Industrial Backplane Interface |
|---|---|
Use Scenario: Buffering ISA/PCIe configuration address lines between southbridge and add-in cards under space-constrained board layout. IC Role / Device Role / Timing Role: Noninverting 3-state buffer providing voltage-level compatibility and bus contention avoidance during hot-plug events. Use Value: Dual OE control allows independent gating of address vs. data lanes; ±8mA drive sustains signal integrity across 10cm backplane traces. |
Use Scenario: Driving parallel control bus signals (e.g., reset, interrupt, enable) across modular PLC chassis with varying module count. IC Role / Device Role / Timing Role: High-drive bus driver isolating master controller from distributed slave modules via 3-state output control. Use Value: 2V–5.5V operation accommodates both 3.3V controllers and 5V legacy modules; 1ns skew prevents setup/hold violations in multi-drop timing. |
| Wearable Health Sensor Hub | Test & Measurement Instrumentation |
Use Scenario: Interfacing low-power MCU GPIOs to multiple analog sensor ADCs requiring precise timing-aligned sampling strobes. IC Role / Device Role / Timing Role: Low-static-current buffer distributing synchronized sample-enable pulses with minimal propagation delay variation. Use Value: 40µA max ICC extends battery life; 3.9ns tPLH at 5V enables sub-100ns strobe edge placement accuracy. |
Use Scenario: Level-shifting and driving high-capacitance probe interface lines in automated test equipment with programmable signal routing. IC Role / Device Role / Timing Role: Overvoltage-tolerant buffer enabling 5V probe logic to interface safely with 3.3V FPGA-based pattern generators. Use Value: 5.5V input tolerance eliminates external clamping diodes; SSOP-20 footprint fits dense instrument PCBs without sacrificing thermal performance. |
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 |
|---|---|---|---|
| SN74AHCT244DBR | TTL-compatible input thresholds (VIH = 2V min at 4.5V VCC); identical pinout and drive strength | Better suited for interfacing with legacy 5V TTL buses where AHC's higher VIH may cause marginal recognition | Select when driving older 5V TTL loads with guaranteed VIH margin; not recommended for 3.3V-only systems due to higher input threshold |
| 74LVC244APW,118 | Lower VCC range (1.65–3.6V); 24mA drive at 3.3V; smaller TSSOP-20 package (4.4mm width) | Optimized for modern low-voltage portable designs; lacks 5V tolerance and industrial temperature range | Select for battery-powered 3.3V systems requiring higher drive and smaller footprint; avoid if 5V interface or –40°C operation needed |
Compared with SN74AHCT244DBR and 74LVC244APW,118, the SN74AHC244DBR uniquely balances 2V–5.5V operation, 5.5V input tolerance, and industrial temperature support - making it the only choice for mixed-voltage, wide-temperature, and legacy-compatible bus buffering.
Availability
SN74AHC244DBR is available at Aetrix Electronics and suitable for PC motherboard design, industrial backplane integration, and wearable sensor hub development requiring stable component supply across extended product lifecycles.
Supply support for SN74AHC244DBR 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 decades of heritage in high-reliability logic families.
The SN74AHC244DBR belongs to TI's advanced high-speed CMOS (AHC) logic portfolio, engineered for robust bus interfacing in computing, industrial automation, and instrumentation where voltage flexibility, timing precision, and ESD resilience are critical.
FAQ
What is the maximum operating temperature for SN74AHC244DBR?
The SN74AHC244DBR is rated for operation from –40°C to +125°C ambient temperature, meeting industrial-grade thermal requirements. This specification is explicitly defined in Section 5.3 "Recommended Operating Conditions" of the official TI datasheet SCLS226N, and applies to all package variants including the DB (SSOP) variant designated by the SN74AHC244DBR part number.
Does SN74AHC244DBR support 3.3V-only operation with 5V-tolerant inputs?
Yes. SN74AHC244DBR operates reliably at VCC = 3.3V while accepting input voltages up to 5.5V on all A-input pins - a key feature confirmed in Section 5.3 (Recommended Operating Conditions) and Section 7.3.4 (Clamp Diode Structure) of the TI datasheet. This enables safe interfacing between 3.3V controllers and 5V peripherals without external level shifters.
What is the output drive capability of SN74AHC244DBR at 3.3V supply?
At VCC = 3.3V ± 0.3V, SN74AHC244DBR delivers ±4mA output current per pin (IOL/IOH), as specified in Table 5.3 of the TI datasheet. This drive level supports reliable switching into 50pF loads with <10ns propagation delay, making it suitable for medium-speed digital interconnects on compact PCBs.
Can unused inputs on SN74AHC244DBR be left floating?
No. All unused inputs on SN74AHC244DBR must be terminated to either VCC or GND to prevent oscillation and excessive power consumption. This requirement is explicitly stated in Section 5.3 footnote (1) and Section 7.3.3 of the TI datasheet, which cites application report SCBA004 on implications of floating CMOS inputs.
Is SN74AHC244DBR pin-compatible with SN74LS244?
No. SN74AHC244DBR is not pin-compatible with SN74LS244. While both are octal 3-state buffers, SN74LS244 uses a different pin assignment (e.g., OE and Y pins occupy distinct positions), has bipolar TTL technology, and lacks 5.5V input tolerance. Direct replacement would require PCB redesign and logic-level revalidation.
SN74AHC244DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 20-SSOP (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-SSOP
SN74AHC244DBR FAQ
1.How can I place an order for SN74AHC244DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC244DBR 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 SN74AHC244DBR reliable?
The price and inventory of SN74AHC244DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC244DBR is usually 5 days.
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SN74AHC244DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC244DBR 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 SN74AHC244DBR?
For technical support, including SN74AHC244DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC244DBR requirements.
6.How does Aetrix verify that SN74AHC244DBR is sourced from the original manufacturer or authorized distributors?
All SN74AHC244DBR 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 SN74AHC244DBR meets industry standards.
7.What is the process for return or replacement of SN74AHC244DBR?
All SN74AHC244DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC244DBR, 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 SN74AHC244DBR part is unused and in its original packaging.
Return procedure for SN74AHC244DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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