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Texas Instruments SN74AHCT244DBR
- Part No.:
- SN74AHCT244DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74AHCT244DBR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:5,152
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Product details
Overview
SN74AHCT244DBR from Texas Instruments is an octal 3-state buffer/driver IC designed for bus interface and memory address driving applications. It features TTL-compatible inputs, 5-V supply operation, ±8-mA output drive, 8.5-ns typical propagation delay (CL = 15 pF), and operates from –40°C to 85°C. It is used in PC motherboard I/O expansion, industrial control backplanes, and embedded system data buses.
For engineers reviewing the SN74AHCT244DBR datasheet, SN74AHCT244DBR pinout, SN74AHCT244DBR application, or SN74AHCT244DBR equivalent, key selection criteria include 3-state bus contention control, 5-V logic compatibility with 3.3-V input tolerance, low-output ringing due to controlled edge rates, and SSOP-20 package suitability for high-density PCB layouts.
Technical Context
The SN74AHCT244DBR implements two independent 4-bit non-inverting buffers, each with dedicated 3-state output-enable (OE) control. Its CMOS design ensures rail-to-rail output swing and low static current (ICC ≤ 40 µA), while TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V) enable direct interfacing with legacy 3.3-V and 5-V logic families.
It supports voltage translation from 3.3-V inputs to 5-V outputs without external level shifters. The device uses slow edge-rate control to suppress output ringing on unterminated transmission lines, making it suitable for noise-sensitive environments such as test equipment and medical data acquisition systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures stable operation across standard 5-V rail tolerances and brown-out immunity. |
| Output Drive | ±8 mA - Sufficient to drive multiple TTL loads or one 50-Ω transmission line without signal degradation. |
| Propagation Delay | 8.5 ns max (CL = 15 pF) - Enables reliable timing in 100-MHz bus cycles with margin for setup/hold. |
| Input Compatibility | TTL-level (VIH = 2 V, VIL = 0.8 V) - Directly accepts 3.3-V LVTTL outputs without level-shifting circuitry. |
| Operating Temperature | –40°C to +85°C - Qualified for commercial and industrial ambient environments including network switch chassis. |
| 3-State Leakage | ±2.5 µA max - Minimizes bus leakage current when outputs are disabled, critical for low-power standby modes. |
| Power Dissipation Cap | 8.2 pF - Low internal capacitance reduces dynamic power consumption at high switching frequencies. |
Pinout & Package
SN74AHCT244DBR is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65-mm lead pitch, 7.2 mm × 7.8 mm body size, and RoHS-compliant NiPdAu lead finish. The package is moisture-sensitive Level-1 (260°C peak reflow) and supplied in 2000-piece tape-and-reel format (reel width 16.4 mm, quadrant Q1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output enables for Group 1 (pins 2,4,6,8 → 12,14,16,18) and Group 2 (pins 11,13,15,17 → 3,5,7,9); controls bus isolation. |
| 2,4,6,8 | 1A1–1A4 | Inputs for first 4-bit buffer group; accept TTL/CMOS logic levels and tolerate up to 5.5 V. |
| 11,13,15,17 | 2A1–2A4 | Inputs for second 4-bit buffer group; electrically isolated from Group 1 for independent bus control. |
| 12,14,16,18 | 1Y1–1Y4 | Non-inverting buffered outputs for Group 1; enter high-impedance state when 1OE = high. |
| 3,5,7,9 | 2Y1–2Y4 | Non-inverting buffered outputs for Group 2; enter high-impedance state when 2OE = high. |
| 10 | GND | Ground reference for all logic and output stages; requires low-inductance connection to minimize ground bounce. |
| 20 | VCC | 5-V power supply pin; must be decoupled with 0.1-µF ceramic capacitor placed within 2 mm of the pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts 3.3-V LVTTL signals directly (VIH = 2 V min, VIL = 0.8 V max), eliminating need for external level shifters in mixed-voltage systems. |
| Controlled edge rates | Slower rise/fall times reduce EMI and output ringing on unterminated traces, improving signal integrity in compact PCB layouts. |
| Independent 3-state control | Dual OE pins allow selective disabling of either 4-bit group, enabling flexible bus arbitration and partial bus isolation. |
| Low quiescent current | ICC ≤ 40 µA at VCC = 5.5 V ensures minimal power draw during idle states, supporting energy-efficient system designs. |
| ESD robustness | ±2000 V HBM rating per JESD22-A114 protects against handling damage during assembly and field service. |
Applications
| PC Motherboard I/O Expansion | Industrial PLC Backplane Interface |
|---|---|
Use Scenario: Isolating legacy ISA or LPC bus signals between southbridge and add-in cards while maintaining signal integrity. IC Role / Device Role / Timing Role: Bidirectional 3-state buffer providing controlled signal routing and bus contention prevention. Use Value: Enables hot-plug-safe I/O expansion via independent OE control and low-output ringing on 10-cm backplane traces. |
Use Scenario: Interfacing microcontroller GPIOs to 24-V digital I/O modules in programmable logic controllers. IC Role / Device Role / Timing Role: Level-translating buffer converting 3.3-V MCU outputs to 5-V logic-compatible signals for optocoupler drivers. Use Value: Eliminates discrete level shifter components while ensuring noise-immune operation in electrically noisy factory environments. |
| Network Switch Data Path | Test Equipment Signal Conditioning |
Use Scenario: Driving parallel status/control lines between ASIC and management microcontroller in 1U rack-mounted switches. IC Role / Device Role / Timing Role: Unidirectional buffer isolating clock-synchronous control signals from shared system bus. Use Value: Prevents bus contention during firmware updates and provides deterministic 8.5-ns propagation for real-time status reporting. |
Use Scenario: Conditioning digital trigger and sync signals in automated test equipment with multi-channel DMMs and SMUs. IC Role / Device Role / Timing Role: Impedance-matched buffer isolating sensitive measurement front-ends from noisy controller logic. Use Value: Reduces crosstalk-induced measurement error by >12 dB through controlled edge rates and low output capacitance (Co = 3 pF). |
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 (1.65–3.6 V), 24-mA drive, 3.5-ns tPD - optimized for 3.3-V-only systems. | Not suitable for 5-V bus interfaces; requires level shifting if interfacing with 5-V peripherals. | Select when full 3.3-V system integration is required and higher speed/low-voltage operation is prioritized. |
| 74AC244SCX | Wider VCC range (2–6 V), 24-mA drive, 5.5-ns tPD - faster but higher power and no TTL input compatibility. | Lacks guaranteed 2-V VIH; may misread 3.3-V LVTTL signals under voltage droop or temperature extremes. | Choose for high-speed 5-V-only buses where input threshold margin is less critical than propagation delay. |
Compared with SN74LVC244APWR and 74AC244SCX, the SN74AHCT244DBR uniquely balances 5-V bus compatibility, TTL input tolerance, and controlled edge rates-making it the preferred choice for mixed-voltage industrial and computing interfaces where signal integrity and interoperability outweigh raw speed.
Availability
SN74AHCT244DBR is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial PLC backplane interfaces, and network switch data path applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for SN74AHCT244DBR 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 industrial, automotive, and communications markets.
The SN74AHCT244DBR belongs to TI's AHCT logic family, engineered for seamless 3.3-V-to-5-V voltage translation and robust bus interfacing in noise-sensitive, high-reliability systems.
FAQ
What is the maximum output current per pin for SN74AHCT244DBR?
The SN74AHCT244DBR supports ±8 mA DC output current per pin under recommended operating conditions (VCC = 4.5–5.5 V, TA = –40°C to +85°C). This rating ensures reliable drive capability into standard TTL loads or 50-Ω transmission lines without exceeding thermal limits or degrading signal fidelity in the SN74AHCT244DBR.
Does SN74AHCT244DBR support 3.3-V input signals?
Yes, the SN74AHCT244DBR accepts 3.3-V LVTTL inputs reliably due to its TTL-compatible input thresholds: VIH = 2.0 V (min) and VIL = 0.8 V (max). This allows direct connection to 3.3-V microcontrollers and FPGAs without external level shifters, a key feature of the SN74AHCT244DBR.
What is the propagation delay of SN74AHCT244DBR at 5-V supply?
The SN74AHCT244DBR exhibits a maximum propagation delay of 8.5 ns (tPLH/tPHL) when driving a 15-pF load at VCC = 5 V and TA = 25°C. This value is confirmed in the switching characteristics table and applies to both input-to-output paths (A→Y and OE→Y), ensuring predictable timing in the SN74AHCT244DBR.
Is SN74AHCT244DBR pin-compatible with other 20-pin octal buffers?
The SN74AHCT244DBR shares the same 20-pin SSOP (DB) footprint and pinout as industry-standard octal buffers like SN74AHCT244DWR and SN74LVC244APWR, but functional differences exist in voltage range and drive strength. Always verify logic thresholds and timing before substitution in the SN74AHCT244DBR design.
What package type does SN74AHCT244DBR use?
The SN74AHCT244DBR uses a 20-pin SSOP (Shrink Small Outline Package) with 0.65-mm lead pitch, 7.2 mm × 7.8 mm body dimensions, and NiPdAu lead finish. It is supplied in tape-and-reel format (2000 units/reel) with MSL Level-1 rating, confirming its suitability for standard surface-mount assembly processes for the SN74AHCT244DBR.
SN74AHCT244DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- 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:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74AHCT244DBR FAQ
1.How can I place an order for SN74AHCT244DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT244DBR 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 SN74AHCT244DBR reliable?
The price and inventory of SN74AHCT244DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT244DBR is usually 5 days.
3.What payment methods are accepted for SN74AHCT244DBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT244DBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT244DBR?
SN74AHCT244DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT244DBR 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 SN74AHCT244DBR?
For technical support, including SN74AHCT244DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT244DBR requirements.
6.How does Aetrix verify that SN74AHCT244DBR is sourced from the original manufacturer or authorized distributors?
All SN74AHCT244DBR 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 SN74AHCT244DBR meets industry standards.
7.What is the process for return or replacement of SN74AHCT244DBR?
All SN74AHCT244DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT244DBR, 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 SN74AHCT244DBR part is unused and in its original packaging.
Return procedure for SN74AHCT244DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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